diff --git a/umap/static/umap/js/components/alerts/alert.js b/umap/static/umap/js/components/alerts/alert.js
index fb37ed6d5..517b79921 100644
--- a/umap/static/umap/js/components/alerts/alert.js
+++ b/umap/static/umap/js/components/alerts/alert.js
@@ -140,7 +140,7 @@ class uMapAlertConflict extends uMapAlert {
     // biome-ignore lint/style/useNumberNamespace: Number.Infinity returns undefined by default
     const {
       level = 'info',
-      duration = Infinity,
+      duration = Number.POSITIVE_INFINITY,
       message = '',
       forceCallback = undefined,
     } = event.detail
diff --git a/umap/static/umap/js/modules/autocomplete.js b/umap/static/umap/js/modules/autocomplete.js
index 48c0cdaa9..0c6972e7b 100644
--- a/umap/static/umap/js/modules/autocomplete.js
+++ b/umap/static/umap/js/modules/autocomplete.js
@@ -1,8 +1,8 @@
 import {
-  DomUtil,
   DomEvent,
-  setOptions,
+  DomUtil,
   Util,
+  setOptions,
 } from '../../vendors/leaflet/leaflet-src.esm.js'
 import { translate } from './i18n.js'
 import { Request, ServerRequest } from './request.js'
diff --git a/umap/static/umap/js/modules/browser.js b/umap/static/umap/js/modules/browser.js
index 64c7cad9b..9a277a7f8 100644
--- a/umap/static/umap/js/modules/browser.js
+++ b/umap/static/umap/js/modules/browser.js
@@ -1,4 +1,4 @@
-import { DomUtil, DomEvent, stamp } from '../../vendors/leaflet/leaflet-src.esm.js'
+import { DomEvent, DomUtil, stamp } from '../../vendors/leaflet/leaflet-src.esm.js'
 import { translate } from './i18n.js'
 
 export default class Browser {
@@ -90,7 +90,7 @@ export default class Browser {
     container.innerHTML = ''
     datalayer.eachFeature((feature) => this.addFeature(feature, container))
 
-    let total = datalayer.count(),
+    const total = datalayer.count(),
       current = container.querySelectorAll('li').length,
       count = total == current ? total : `${current}/${total}`
     const counter = DomUtil.create('span', 'datalayer-counter', headline)
diff --git a/umap/static/umap/js/modules/caption.js b/umap/static/umap/js/modules/caption.js
index a5557c5d4..a17a57e90 100644
--- a/umap/static/umap/js/modules/caption.js
+++ b/umap/static/umap/js/modules/caption.js
@@ -18,7 +18,7 @@ export default class Caption {
 
   open() {
     const container = DomUtil.create('div', 'umap-caption')
-    const hgroup = DomUtil.element({tagName: 'hgroup', parent: container})
+    const hgroup = DomUtil.element({ tagName: 'hgroup', parent: container })
     DomUtil.createTitle(hgroup, this.map.options.name, 'icon-caption icon-block')
     this.map.permissions.addOwnerLink('h4', hgroup)
     if (this.map.options.description) {
diff --git a/umap/static/umap/js/modules/dompurify.js b/umap/static/umap/js/modules/dompurify.js
index e82197416..74d75ed72 100644
--- a/umap/static/umap/js/modules/dompurify.js
+++ b/umap/static/umap/js/modules/dompurify.js
@@ -1,5 +1,5 @@
-import { default as DOMPurifyInitializer } from '../../vendors/dompurify/purify.es.js'
 import { JSDOM } from 'jsdom'
+import { default as DOMPurifyInitializer } from '../../vendors/dompurify/purify.es.js'
 
 console.log(DOMPurifyInitializer)
 
diff --git a/umap/static/umap/js/modules/facets.js b/umap/static/umap/js/modules/facets.js
index 461a8ec31..47e266fe0 100644
--- a/umap/static/umap/js/modules/facets.js
+++ b/umap/static/umap/js/modules/facets.js
@@ -1,4 +1,4 @@
-import { DomUtil, DomEvent, stamp } from '../../vendors/leaflet/leaflet-src.esm.js'
+import { DomEvent, DomUtil, stamp } from '../../vendors/leaflet/leaflet-src.esm.js'
 import { translate } from './i18n.js'
 import * as Utils from './utils.js'
 
@@ -57,7 +57,7 @@ export default class Facets {
   }
 
   isActive() {
-    for (let { type, min, max, choices } of Object.values(this.selected)) {
+    for (const { type, min, max, choices } of Object.values(this.selected)) {
       if (min !== undefined || max != undefined || choices?.length) {
         return true
       }
@@ -71,7 +71,7 @@ export default class Facets {
     const facetProperties = this.compute(names, defined)
 
     const fields = names.map((name) => {
-      let criteria = facetProperties[name]
+      const criteria = facetProperties[name]
       let handler = 'FacetSearchChoices'
       switch (criteria['type']) {
         case 'number':
@@ -84,7 +84,7 @@ export default class Facets {
           handler = 'FacetSearchDateTime'
           break
       }
-      let label = defined[name]['label']
+      const label = defined[name]['label']
       return [
         `selected.${name}`,
         {
@@ -112,7 +112,7 @@ export default class Facets {
   getParser(type) {
     switch (type) {
       case 'number':
-        return parseFloat
+        return Number.parseFloat
       case 'datetime':
         return (v) => new Date(v)
       case 'date':
diff --git a/umap/static/umap/js/modules/global.js b/umap/static/umap/js/modules/global.js
index 49f2822b7..c4eebe03e 100644
--- a/umap/static/umap/js/modules/global.js
+++ b/umap/static/umap/js/modules/global.js
@@ -1,24 +1,24 @@
-import URLs from './urls.js'
+import {
+  uMapAlert as Alert,
+  uMapAlertConflict as AlertConflict,
+  uMapAlertCreation as AlertCreation,
+} from '../components/alerts/alert.js'
+import { AjaxAutocomplete, AjaxAutocompleteMultiple } from './autocomplete.js'
 import Browser from './browser.js'
-import Facets from './facets.js'
 import Caption from './caption.js'
-import { Panel, EditPanel, FullPanel } from './ui/panel.js'
-import Dialog from './ui/dialog.js'
-import Tooltip from './ui/tooltip.js'
+import Facets from './facets.js'
+import Help from './help.js'
+import Importer from './importer.js'
+import Orderable from './orderable.js'
+import { HTTPError, NOKError, Request, RequestError, ServerRequest } from './request.js'
 import Rules from './rules.js'
-import * as Utils from './utils.js'
 import { SCHEMA } from './schema.js'
-import { Request, ServerRequest, RequestError, HTTPError, NOKError } from './request.js'
-import { AjaxAutocomplete, AjaxAutocompleteMultiple } from './autocomplete.js'
-import Orderable from './orderable.js'
-import Importer from './importer.js'
-import Help from './help.js'
 import { SyncEngine } from './sync/engine.js'
-import {
-  uMapAlert as Alert,
-  uMapAlertCreation as AlertCreation,
-  uMapAlertConflict as AlertConflict,
-} from '../components/alerts/alert.js'
+import Dialog from './ui/dialog.js'
+import { EditPanel, FullPanel, Panel } from './ui/panel.js'
+import Tooltip from './ui/tooltip.js'
+import URLs from './urls.js'
+import * as Utils from './utils.js'
 
 // Import modules and export them to the global scope.
 // For the not yet module-compatible JS out there.
diff --git a/umap/static/umap/js/modules/help.js b/umap/static/umap/js/modules/help.js
index 74c2b9f2c..580d97cd6 100644
--- a/umap/static/umap/js/modules/help.js
+++ b/umap/static/umap/js/modules/help.js
@@ -1,4 +1,4 @@
-import { DomUtil, DomEvent } from '../../vendors/leaflet/leaflet-src.esm.js'
+import { DomEvent, DomUtil } from '../../vendors/leaflet/leaflet-src.esm.js'
 import { translate } from './i18n.js'
 
 const SHORTCUTS = {
diff --git a/umap/static/umap/js/modules/importer.js b/umap/static/umap/js/modules/importer.js
index 8ced13bf4..cca118068 100644
--- a/umap/static/umap/js/modules/importer.js
+++ b/umap/static/umap/js/modules/importer.js
@@ -1,8 +1,8 @@
-import { DomUtil, DomEvent } from '../../vendors/leaflet/leaflet-src.esm.js'
-import { translate } from './i18n.js'
+import { DomEvent, DomUtil } from '../../vendors/leaflet/leaflet-src.esm.js'
 import { uMapAlert as Alert } from '../components/alerts/alert.js'
-import Dialog from './ui/dialog.js'
+import { translate } from './i18n.js'
 import { SCHEMA } from './schema.js'
+import Dialog from './ui/dialog.js'
 import * as Utils from './utils.js'
 
 const TEMPLATE = `
diff --git a/umap/static/umap/js/modules/importers/geodatamine.js b/umap/static/umap/js/modules/importers/geodatamine.js
index 5c73be009..74c2819b4 100644
--- a/umap/static/umap/js/modules/importers/geodatamine.js
+++ b/umap/static/umap/js/modules/importers/geodatamine.js
@@ -1,8 +1,8 @@
-import { DomUtil, DomEvent } from '../../../vendors/leaflet/leaflet-src.esm.js'
+import { DomEvent, DomUtil } from '../../../vendors/leaflet/leaflet-src.esm.js'
+import { uMapAlert as Alert } from '../../components/alerts/alert.js'
 import { BaseAjax, SingleMixin } from '../autocomplete.js'
 import { translate } from '../i18n.js'
 import * as Utils from '../utils.js'
-import { uMapAlert as Alert } from '../../components/alerts/alert.js'
 
 const BOUNDARY_TYPES = {
   admin_6: 'département',
@@ -54,7 +54,7 @@ export class Importer {
     const select = container.querySelector('select')
     if (response && response.ok) {
       const { themes } = await response.json()
-      themes.sort((a, b) => Utils.naturalSort(a['name:fr'], b ['name:fr']))
+      themes.sort((a, b) => Utils.naturalSort(a['name:fr'], b['name:fr']))
       for (const theme of themes) {
         DomUtil.element({
           tagName: 'option',
diff --git a/umap/static/umap/js/modules/importers/overpass.js b/umap/static/umap/js/modules/importers/overpass.js
index 8d7d5ac8c..8bd7f058d 100644
--- a/umap/static/umap/js/modules/importers/overpass.js
+++ b/umap/static/umap/js/modules/importers/overpass.js
@@ -1,7 +1,7 @@
 import { DomUtil } from '../../../vendors/leaflet/leaflet-src.esm.js'
+import { uMapAlert as Alert } from '../../components/alerts/alert.js'
 import { BaseAjax, SingleMixin } from '../autocomplete.js'
 import { translate } from '../i18n.js'
-import { uMapAlert as Alert } from '../../components/alerts/alert.js'
 
 const TEMPLATE = `
   <h3>Overpass</h3>
@@ -68,7 +68,7 @@ export class Importer {
       if (!tags.startsWith('[')) tags = `[${tags}]`
       let area = '{south},{west},{north},{east}'
       if (boundary) area = `area:${boundary}`
-      let query = `[out:json];nwr${tags}(${area});out ${outMode};`
+      const query = `[out:json];nwr${tags}(${area});out ${outMode};`
       importer.url = `${this.baseUrl}?data=${query}`
       if (boundary) importer.layerName = boundaryName
       importer.format = 'osm'
diff --git a/umap/static/umap/js/modules/request.js b/umap/static/umap/js/modules/request.js
index 3edc6ba8f..c8525363b 100644
--- a/umap/static/umap/js/modules/request.js
+++ b/umap/static/umap/js/modules/request.js
@@ -1,5 +1,5 @@
-import { translate } from './i18n.js'
 import { uMapAlert as Alert } from '../components/alerts/alert.js'
+import { translate } from './i18n.js'
 
 export class RequestError extends Error {}
 
diff --git a/umap/static/umap/js/modules/rules.js b/umap/static/umap/js/modules/rules.js
index e89d6a8f8..b3e06dd9e 100644
--- a/umap/static/umap/js/modules/rules.js
+++ b/umap/static/umap/js/modules/rules.js
@@ -1,9 +1,8 @@
-import { DomUtil, DomEvent, stamp } from '../../vendors/leaflet/leaflet-src.esm.js'
-import * as Utils from './utils.js'
+import { DomEvent, DomUtil, stamp } from '../../vendors/leaflet/leaflet-src.esm.js'
 import { translate } from './i18n.js'
+import * as Utils from './utils.js'
 
 class Rule {
-
   get condition() {
     return this._condition
   }
@@ -13,7 +12,6 @@ class Rule {
     this.parse()
   }
 
-
   get isDirty() {
     return this._isDirty
   }
@@ -76,7 +74,7 @@ class Rule {
     if (vars.length != 2) return
     this.key = vars[0]
     this.expected = vars[1]
-    if (!isNaN(this.expected)) this.cast = parseFloat
+    if (!isNaN(this.expected)) this.cast = Number.parseFloat
     else if (['true', 'false'].includes(this.expected)) this.cast = (v) => !!v
     this.expected = this.cast(this.expected)
   }
diff --git a/umap/static/umap/js/modules/sync/engine.js b/umap/static/umap/js/modules/sync/engine.js
index 2af5dfb68..6b672aa75 100644
--- a/umap/static/umap/js/modules/sync/engine.js
+++ b/umap/static/umap/js/modules/sync/engine.js
@@ -1,5 +1,5 @@
+import { DataLayerUpdater, FeatureUpdater, MapUpdater } from './updaters.js'
 import { WebSocketTransport } from './websocket.js'
-import { MapUpdater, DataLayerUpdater, FeatureUpdater } from './updaters.js'
 
 export class SyncEngine {
   constructor(map) {
@@ -37,7 +37,7 @@ export class SyncEngine {
   // This method is called by the transport layer on new messages
   receive({ kind, ...payload }) {
     if (kind == 'operation') {
-      let updater = this._getUpdater(payload.subject, payload.metadata)
+      const updater = this._getUpdater(payload.subject, payload.metadata)
       updater.applyMessage(payload)
     } else {
       throw new Error(`Unknown dispatch kind: ${kind}`)
diff --git a/umap/static/umap/js/modules/sync/updaters.js b/umap/static/umap/js/modules/sync/updaters.js
index a64e351dd..faaf79203 100644
--- a/umap/static/umap/js/modules/sync/updaters.js
+++ b/umap/static/umap/js/modules/sync/updaters.js
@@ -35,7 +35,7 @@ class BaseUpdater {
   }
 
   applyMessage(payload) {
-    let { verb } = payload
+    const { verb } = payload
     return this[verb](payload)
   }
 }
@@ -69,7 +69,7 @@ export class FeatureUpdater extends BaseUpdater {
 
   // Create or update an object at a specific position
   upsert({ metadata, value }) {
-    let { id, layerId } = metadata
+    const { id, layerId } = metadata
     const datalayer = this.getDataLayerFromID(layerId)
     let feature = this.getFeatureFromMetadata(metadata, value)
 
@@ -84,7 +84,7 @@ export class FeatureUpdater extends BaseUpdater {
 
   // Update a property of an object
   update({ key, metadata, value }) {
-    let feature = this.getFeatureFromMetadata(metadata)
+    const feature = this.getFeatureFromMetadata(metadata)
     if (feature === undefined) {
       console.error(`Unable to find feature with id = ${metadata.id}.`)
     }
@@ -103,7 +103,7 @@ export class FeatureUpdater extends BaseUpdater {
   delete({ metadata }) {
     // XXX Distinguish between properties getting deleted
     // and the wole feature getting deleted
-    let feature = this.getFeatureFromMetadata(metadata)
+    const feature = this.getFeatureFromMetadata(metadata)
     if (feature) feature.del(false)
   }
 }
diff --git a/umap/static/umap/js/modules/sync/websocket.js b/umap/static/umap/js/modules/sync/websocket.js
index 45854dc11..529c0b190 100644
--- a/umap/static/umap/js/modules/sync/websocket.js
+++ b/umap/static/umap/js/modules/sync/websocket.js
@@ -15,7 +15,7 @@ export class WebSocketTransport {
   send(kind, payload) {
     const message = { ...payload }
     message.kind = kind
-    let encoded = JSON.stringify(message)
+    const encoded = JSON.stringify(message)
     this.websocket.send(encoded)
   }
 
diff --git a/umap/static/umap/js/modules/ui/dialog.js b/umap/static/umap/js/modules/ui/dialog.js
index f85b7d544..9cfea1b19 100644
--- a/umap/static/umap/js/modules/ui/dialog.js
+++ b/umap/static/umap/js/modules/ui/dialog.js
@@ -1,4 +1,4 @@
-import { DomUtil, DomEvent } from '../../../vendors/leaflet/leaflet-src.esm.js'
+import { DomEvent, DomUtil } from '../../../vendors/leaflet/leaflet-src.esm.js'
 import { translate } from '../i18n.js'
 
 export default class Dialog {
diff --git a/umap/static/umap/js/modules/ui/panel.js b/umap/static/umap/js/modules/ui/panel.js
index e236e82ab..f84a92b30 100644
--- a/umap/static/umap/js/modules/ui/panel.js
+++ b/umap/static/umap/js/modules/ui/panel.js
@@ -1,4 +1,4 @@
-import { DomUtil, DomEvent } from '../../../vendors/leaflet/leaflet-src.esm.js'
+import { DomEvent, DomUtil } from '../../../vendors/leaflet/leaflet-src.esm.js'
 import { translate } from '../i18n.js'
 
 export class Panel {
diff --git a/umap/static/umap/js/modules/ui/tooltip.js b/umap/static/umap/js/modules/ui/tooltip.js
index 6573421d3..eb95b8094 100644
--- a/umap/static/umap/js/modules/ui/tooltip.js
+++ b/umap/static/umap/js/modules/ui/tooltip.js
@@ -1,4 +1,4 @@
-import { DomUtil, DomEvent } from '../../../vendors/leaflet/leaflet-src.esm.js'
+import { DomEvent, DomUtil } from '../../../vendors/leaflet/leaflet-src.esm.js'
 import { translate } from '../i18n.js'
 
 export default class Tooltip {
@@ -34,7 +34,7 @@ export default class Tooltip {
     if (opts.anchor) {
       L.DomEvent.once(opts.anchor, 'mouseout', closeIt)
     }
-    if (opts.duration !== Infinity) {
+    if (opts.duration !== Number.POSITIVE_INFINITY) {
       window.setTimeout(closeIt, opts.duration || 3000)
     }
   }
diff --git a/umap/static/umap/js/modules/utils.js b/umap/static/umap/js/modules/utils.js
index 0ebb885a5..c132f1a51 100644
--- a/umap/static/umap/js/modules/utils.js
+++ b/umap/static/umap/js/modules/utils.js
@@ -36,7 +36,7 @@ export function checkId(string) {
  */
 export function getImpactsFromSchema(fields, schema) {
   schema = schema || U.SCHEMA
-  let impacted = fields
+  const impacted = fields
     .map((field) => {
       // remove the option prefix for fields
       // And only keep the first part in case of a subfield
@@ -120,7 +120,7 @@ export function toHTML(r, options) {
   r = r.replace(/^\*\* (.*)/gm, '<ul><ul><li>$1</li></ul></ul>')
   r = r.replace(/^\* (.*)/gm, '<ul><li>$1</li></ul>')
   for (let ii = 0; ii < 3; ii++) {
-    r = r.replace(new RegExp(`</ul>(\r\n|\r|\n)<ul>`, 'g'), '')
+    r = r.replace(/<\/ul>(\r\n|\r|\n)<ul>/g, '')
   }
 
   // headings and hr
@@ -352,7 +352,7 @@ export function normalize(s) {
 var templateRe = /\{ *([\w_ -]+) *\}/g
 
 export function template(str, data) {
-  return str.replace(templateRe, function (str, key) {
+  return str.replace(templateRe, (str, key) => {
     var value = data[key]
 
     if (value === undefined) {
diff --git a/umap/static/umap/js/umap.controls.js b/umap/static/umap/js/umap.controls.js
index 0417319d6..dab123785 100644
--- a/umap/static/umap/js/umap.controls.js
+++ b/umap/static/umap/js/umap.controls.js
@@ -162,7 +162,7 @@ U.BaseFeatureAction = L.ToolbarAction.extend({
     this.postInit()
   },
 
-  postInit: function () {},
+  postInit: () => {},
 
   hideToolbar: function () {
     this.map.removeLayer(this.toolbar)
@@ -356,7 +356,7 @@ U.DropControl = L.Class.extend({
     this.dropzone.classList.add('umap-dragover')
   },
 
-  dragover: function (e) {
+  dragover: (e) => {
     L.DomEvent.stop(e)
   },
 
@@ -393,7 +393,7 @@ U.EditControl = L.Control.extend({
     L.DomEvent.on(
       enableEditing,
       'mouseover',
-      function () {
+      () => {
         map.tooltip.open({
           content: map.help.displayLabel('TOGGLE_EDIT'),
           anchor: enableEditing,
@@ -503,7 +503,7 @@ L.Control.Button = L.Control.extend({
     return container
   },
 
-  afterAdd: function (container) {},
+  afterAdd: (container) => {},
 })
 
 U.DataLayersControl = L.Control.Button.extend({
@@ -1205,9 +1205,7 @@ L.Control.MiniMap.include({
     this._miniMap.addLayer(this._layer)
   },
 
-  _cloneLayer: function (layer) {
-    return new L.TileLayer(layer._url, L.Util.extend({}, layer.options))
-  },
+  _cloneLayer: (layer) => new L.TileLayer(layer._url, L.Util.extend({}, layer.options)),
 })
 
 L.Control.Loading.include({
@@ -1364,7 +1362,7 @@ U.Editable = L.Editable.extend({
     this.map.ui.closeTooltip()
   },
 
-  onVertexRawClick: function (e) {
+  onVertexRawClick: (e) => {
     e.layer.onVertexRawClick(e)
     L.DomEvent.stop(e)
     e.cancel()
diff --git a/umap/static/umap/js/umap.core.js b/umap/static/umap/js/umap.core.js
index c0aac7c75..4ae9e465f 100644
--- a/umap/static/umap/js/umap.core.js
+++ b/umap/static/umap/js/umap.core.js
@@ -1,4 +1,4 @@
-L.Util.copyToClipboard = function (textToCopy) {
+L.Util.copyToClipboard = (textToCopy) => {
   // https://stackoverflow.com/a/65996386
   // Navigator clipboard api needs a secure context (https)
   if (navigator.clipboard && window.isSecureContext) {
@@ -25,7 +25,7 @@ L.Util.copyToClipboard = function (textToCopy) {
   }
 }
 
-L.Util.queryString = function (name, fallback) {
+L.Util.queryString = (name, fallback) => {
   const decode = (s) => decodeURIComponent(s.replace(/\+/g, ' '))
   const qs = window.location.search.slice(1).split('&'),
     qa = {}
@@ -37,27 +37,27 @@ L.Util.queryString = function (name, fallback) {
   return qa[name] || fallback
 }
 
-L.Util.booleanFromQueryString = function (name) {
+L.Util.booleanFromQueryString = (name) => {
   const value = L.Util.queryString(name)
   return value === '1' || value === 'true'
 }
 
-L.Util.setFromQueryString = function (options, name) {
+L.Util.setFromQueryString = (options, name) => {
   const value = L.Util.queryString(name)
   if (typeof value !== 'undefined') options[name] = value
 }
 
-L.Util.setBooleanFromQueryString = function (options, name) {
+L.Util.setBooleanFromQueryString = (options, name) => {
   const value = L.Util.queryString(name)
   if (typeof value !== 'undefined') options[name] = value == '1' || value == 'true'
 }
 
-L.Util.setNumberFromQueryString = function (options, name) {
+L.Util.setNumberFromQueryString = (options, name) => {
   const value = +L.Util.queryString(name)
   if (!isNaN(value)) options[name] = value
 }
 
-L.Util.setNullableBooleanFromQueryString = function (options, name) {
+L.Util.setNullableBooleanFromQueryString = (options, name) => {
   let value = L.Util.queryString(name)
   if (typeof value !== 'undefined') {
     if (value === 'null') value = null
@@ -222,7 +222,11 @@ L.DomUtil.contrastedColor = (el, bgcolor) => {
   let rgb = window.getComputedStyle(el).getPropertyValue('background-color')
   rgb = L.DomUtil.RGBRegex.exec(rgb)
   if (!rgb || rgb.length !== 4) return out
-  rgb = [parseInt(rgb[1], 10), parseInt(rgb[2], 10), parseInt(rgb[3], 10)]
+  rgb = [
+    Number.parseInt(rgb[1], 10),
+    Number.parseInt(rgb[2], 10),
+    Number.parseInt(rgb[3], 10),
+  ]
   out = L.DomUtil.contrastWCAG21(rgb)
   if (bgcolor) _CACHE_CONSTRAST[bgcolor] = out
   return out
diff --git a/umap/static/umap/js/umap.datalayer.permissions.js b/umap/static/umap/js/umap.datalayer.permissions.js
index f65b05dc3..5ff813022 100644
--- a/umap/static/umap/js/umap.datalayer.permissions.js
+++ b/umap/static/umap/js/umap.datalayer.permissions.js
@@ -7,15 +7,12 @@ U.DataLayerPermissions = L.Class.extend({
     this.options = L.Util.setOptions(this, datalayer.options.permissions)
     this.datalayer = datalayer
     let isDirty = false
-    const self = this
     try {
       Object.defineProperty(this, 'isDirty', {
-        get: function () {
-          return isDirty
-        },
-        set: function (status) {
+        get: () => isDirty,
+        set: (status) => {
           isDirty = status
-          if (status) self.datalayer.isDirty = status
+          if (status) this.datalayer.isDirty = status
         },
       })
     } catch (e) {
diff --git a/umap/static/umap/js/umap.features.js b/umap/static/umap/js/umap.features.js
index 6f9b12986..105f393a2 100644
--- a/umap/static/umap/js/umap.features.js
+++ b/umap/static/umap/js/umap.features.js
@@ -58,19 +58,16 @@ U.FeatureMixin = {
       }
     }
     let isDirty = false
-    const self = this
     try {
       Object.defineProperty(this, 'isDirty', {
-        get: function () {
-          return isDirty
-        },
-        set: function (status) {
+        get: () => isDirty,
+        set: (status) => {
           if (!isDirty && status) {
-            self.fire('isdirty')
+            this.fire('isdirty')
           }
           isDirty = status
-          if (self.datalayer) {
-            self.datalayer.isDirty = status
+          if (this.datalayer) {
+            this.datalayer.isDirty = status
           }
         },
       })
@@ -82,7 +79,7 @@ U.FeatureMixin = {
     this.parentClass.prototype.initialize.call(this, latlng, options)
   },
 
-  preInit: function () {},
+  preInit: () => {},
 
   isReadOnly: function () {
     return this.datalayer && this.datalayer.isDataReadOnly()
@@ -228,19 +225,17 @@ U.FeatureMixin = {
     popupFieldset.appendChild(builder.build())
   },
 
-  getInteractionOptions: function () {
-    return [
-      'properties._umap_options.popupShape',
-      'properties._umap_options.popupTemplate',
-      'properties._umap_options.showLabel',
-      'properties._umap_options.labelDirection',
-      'properties._umap_options.labelInteractive',
-      'properties._umap_options.outlink',
-      'properties._umap_options.outlinkTarget',
-    ]
-  },
+  getInteractionOptions: () => [
+    'properties._umap_options.popupShape',
+    'properties._umap_options.popupTemplate',
+    'properties._umap_options.showLabel',
+    'properties._umap_options.labelDirection',
+    'properties._umap_options.labelInteractive',
+    'properties._umap_options.outlink',
+    'properties._umap_options.outlinkTarget',
+  ],
 
-  endEdit: function () {},
+  endEdit: () => {},
 
   getDisplayName: function (fallback) {
     if (fallback === undefined) fallback = this.datalayer.options.name
@@ -298,7 +293,7 @@ U.FeatureMixin = {
     }
   },
 
-  cleanProperty: function ([key, value]) {
+  cleanProperty: ([key, value]) => {
     // dot in key will break the dot based property access
     // while editing the feature
     key = key.replace('.', '_')
@@ -434,13 +429,9 @@ U.FeatureMixin = {
     L.DomEvent.stop(e)
   },
 
-  getPopupToolbarAnchor: function () {
-    return [0, 0]
-  },
+  getPopupToolbarAnchor: () => [0, 0],
 
-  getInplaceToolbarActions: function (e) {
-    return [U.ToggleEditAction, U.DeleteFeatureAction]
-  },
+  getInplaceToolbarActions: (e) => [U.ToggleEditAction, U.DeleteFeatureAction],
 
   _showContextMenu: function (e) {
     L.DomEvent.stop(e)
@@ -463,7 +454,7 @@ U.FeatureMixin = {
     if (permalink)
       items.push({
         text: L._('Permalink'),
-        callback: function () {
+        callback: () => {
           window.open(permalink)
         },
       })
@@ -554,9 +545,9 @@ U.FeatureMixin = {
 
   matchFacets: function () {
     const selected = this.map.facets.selected
-    for (let [name, { type, min, max, choices }] of Object.entries(selected)) {
+    for (const [name, { type, min, max, choices }] of Object.entries(selected)) {
       let value = this.properties[name]
-      let parser = this.map.facets.getParser(type)
+      const parser = this.map.facets.getParser(type)
       value = parser(value)
       switch (type) {
         case 'date':
@@ -581,13 +572,9 @@ U.FeatureMixin = {
     }).addTo(this.map, this, e.latlng, e.vertex)
   },
 
-  getVertexActions: function () {
-    return [U.DeleteVertexAction]
-  },
+  getVertexActions: () => [U.DeleteVertexAction],
 
-  isMulti: function () {
-    return false
-  },
+  isMulti: () => false,
 
   clone: function () {
     const geoJSON = this.toGeoJSON()
@@ -746,22 +733,16 @@ U.Marker = L.Marker.extend({
     return this._latlng
   },
 
-  getClassName: function () {
-    return 'marker'
-  },
+  getClassName: () => 'marker',
 
-  getShapeOptions: function () {
-    return [
-      'properties._umap_options.color',
-      'properties._umap_options.iconClass',
-      'properties._umap_options.iconUrl',
-      'properties._umap_options.iconOpacity',
-    ]
-  },
+  getShapeOptions: () => [
+    'properties._umap_options.color',
+    'properties._umap_options.iconClass',
+    'properties._umap_options.iconUrl',
+    'properties._umap_options.iconOpacity',
+  ],
 
-  getAdvancedOptions: function () {
-    return ['properties._umap_options.zoomTo']
-  },
+  getAdvancedOptions: () => ['properties._umap_options.zoomTo'],
 
   appendEditFieldsets: function (container) {
     U.FeatureMixin.appendEditFieldsets.call(this, container)
@@ -847,21 +828,17 @@ U.PathMixin = {
     'interactive',
   ],
 
-  getShapeOptions: function () {
-    return [
-      'properties._umap_options.color',
-      'properties._umap_options.opacity',
-      'properties._umap_options.weight',
-    ]
-  },
+  getShapeOptions: () => [
+    'properties._umap_options.color',
+    'properties._umap_options.opacity',
+    'properties._umap_options.weight',
+  ],
 
-  getAdvancedOptions: function () {
-    return [
-      'properties._umap_options.smoothFactor',
-      'properties._umap_options.dashArray',
-      'properties._umap_options.zoomTo',
-    ]
-  },
+  getAdvancedOptions: () => [
+    'properties._umap_options.smoothFactor',
+    'properties._umap_options.dashArray',
+    'properties._umap_options.zoomTo',
+  ],
 
   setStyle: function (options) {
     options = options || {}
@@ -1070,13 +1047,9 @@ U.Polyline = L.Polyline.extend({
     mainColor: 'color',
   },
 
-  isSameClass: function (other) {
-    return other instanceof U.Polyline
-  },
+  isSameClass: (other) => other instanceof U.Polyline,
 
-  getClassName: function () {
-    return 'polyline'
-  },
+  getClassName: () => 'polyline',
 
   getMeasure: function (shape) {
     const length = L.GeoUtil.lineLength(this.map, shape || this._defaultShape())
@@ -1214,15 +1187,11 @@ U.Polygon = L.Polygon.extend({
     mainColor: 'fillColor',
   },
 
-  isSameClass: function (other) {
-    return other instanceof U.Polygon
-  },
+  isSameClass: (other) => other instanceof U.Polygon,
 
-  getClassName: function () {
-    return 'polygon'
-  },
+  getClassName: () => 'polygon',
 
-  getShapeOptions: function () {
+  getShapeOptions: () => {
     const options = U.PathMixin.getShapeOptions()
     options.push(
       'properties._umap_options.stroke',
@@ -1233,7 +1202,7 @@ U.Polygon = L.Polygon.extend({
     return options
   },
 
-  getInteractionOptions: function () {
+  getInteractionOptions: () => {
     const options = U.FeatureMixin.getInteractionOptions()
     options.push('properties._umap_options.interactive')
     return options
diff --git a/umap/static/umap/js/umap.forms.js b/umap/static/umap/js/umap.forms.js
index a822cd9d8..6a15e93e5 100644
--- a/umap/static/umap/js/umap.forms.js
+++ b/umap/static/umap/js/umap.forms.js
@@ -296,10 +296,9 @@ L.FormBuilder.ColorPicker = L.FormBuilder.Input.extend({
   },
 
   onBlur: function () {
-    const self = this,
-      closePicker = () => {
-        self.container.style.display = 'none'
-      }
+    const closePicker = () => {
+      this.container.style.display = 'none'
+    }
     // We must leave time for the click to be listened.
     window.setTimeout(closePicker, 100)
   },
@@ -341,7 +340,7 @@ L.FormBuilder.TextColorPicker = L.FormBuilder.ColorPicker.extend({
 })
 
 L.FormBuilder.LayerTypeChooser = L.FormBuilder.Select.extend({
-  getOptions: function () {
+  getOptions: () => {
     const layer_classes = [
       U.Layer.Default,
       U.Layer.Cluster,
@@ -353,7 +352,7 @@ L.FormBuilder.LayerTypeChooser = L.FormBuilder.Select.extend({
 })
 
 L.FormBuilder.SlideshowDelay = L.FormBuilder.IntSelect.extend({
-  getOptions: function () {
+  getOptions: () => {
     const options = []
     for (let i = 1; i < 30; i++) {
       options.push([i * 1000, L._('{delay} seconds', { delay: i })])
@@ -459,9 +458,7 @@ L.FormBuilder.BlurInput.include({
 })
 
 L.FormBuilder.IconUrl = L.FormBuilder.BlurInput.extend({
-  type: function () {
-    return 'hidden'
-  },
+  type: () => 'hidden',
 
   build: function () {
     L.FormBuilder.BlurInput.prototype.build.call(this)
@@ -547,10 +544,10 @@ L.FormBuilder.IconUrl = L.FormBuilder.BlurInput.extend({
 
   openTab: function (name) {
     const els = this.tabs.querySelectorAll('button')
-    for (let el of els) {
+    for (const el of els) {
       L.DomUtil.removeClass(el, 'on')
     }
-    let el = this.tabs.querySelector(`.tab-${name}`)
+    const el = this.tabs.querySelector(`.tab-${name}`)
     L.DomUtil.addClass(el, 'on')
     this.body.innerHTML = ''
   },
@@ -612,7 +609,7 @@ L.FormBuilder.IconUrl = L.FormBuilder.BlurInput.extend({
     if (name) L.DomUtil.add('h6', '', parent, name)
     const grid = L.DomUtil.create('div', 'umap-pictogram-grid', parent)
     let status = false
-    for (let item of items) {
+    for (const item of items) {
       status = this.addIconPreview(item, grid) || status
     }
     if (status) this.grid.appendChild(parent)
@@ -630,7 +627,7 @@ L.FormBuilder.IconUrl = L.FormBuilder.BlurInput.extend({
     const sorted = Object.entries(categories).toSorted(([a], [b]) =>
       U.Utils.naturalSort(a, b, L.lang)
     )
-    for (let [name, items] of sorted) {
+    for (const [name, items] of sorted) {
       this.addCategory(items, name)
     }
   },
@@ -701,7 +698,7 @@ L.FormBuilder.IconUrl = L.FormBuilder.BlurInput.extend({
     return input
   },
 
-  unselectAll: function (container) {
+  unselectAll: (container) => {
     const els = container.querySelectorAll('div.selected')
     for (const el in els) {
       if (els.hasOwnProperty(el)) L.DomUtil.removeClass(els[el], 'selected')
@@ -710,9 +707,7 @@ L.FormBuilder.IconUrl = L.FormBuilder.BlurInput.extend({
 })
 
 L.FormBuilder.Url = L.FormBuilder.Input.extend({
-  type: function () {
-    return 'url'
-  },
+  type: () => 'url',
 })
 
 L.FormBuilder.Switch = L.FormBuilder.CheckBox.extend({
@@ -780,17 +775,11 @@ L.FormBuilder.FacetSearchChoices = L.FormBuilder.FacetSearchBase.extend({
 })
 
 L.FormBuilder.MinMaxBase = L.FormBuilder.FacetSearchBase.extend({
-  getInputType: function (type) {
-    return type
-  },
+  getInputType: (type) => type,
 
-  getLabels: function () {
-    return [L._('Min'), L._('Max')]
-  },
+  getLabels: () => [L._('Min'), L._('Max')],
 
-  prepareForHTML: function (value) {
-    return value.valueOf()
-  },
+  prepareForHTML: (value) => value.valueOf(),
 
   build: function () {
     this.container = L.DomUtil.create('fieldset', 'umap-facet', this.parentNode)
@@ -880,19 +869,13 @@ L.FormBuilder.MinMaxBase = L.FormBuilder.FacetSearchBase.extend({
 })
 
 L.FormBuilder.FacetSearchNumber = L.FormBuilder.MinMaxBase.extend({
-  prepareForJS: function (value) {
-    return new Number(value)
-  },
+  prepareForJS: (value) => new Number(value),
 })
 
 L.FormBuilder.FacetSearchDate = L.FormBuilder.MinMaxBase.extend({
-  prepareForJS: function (value) {
-    return new Date(value)
-  },
+  prepareForJS: (value) => new Date(value),
 
-  toLocaleDateTime: function (dt) {
-    return new Date(dt.valueOf() - dt.getTimezoneOffset() * 60000)
-  },
+  toLocaleDateTime: (dt) => new Date(dt.valueOf() - dt.getTimezoneOffset() * 60000),
 
   prepareForHTML: function (value) {
     // Value must be in local time
@@ -900,15 +883,11 @@ L.FormBuilder.FacetSearchDate = L.FormBuilder.MinMaxBase.extend({
     return this.toLocaleDateTime(value).toISOString().substr(0, 10)
   },
 
-  getLabels: function () {
-    return [L._('From'), L._('Until')]
-  },
+  getLabels: () => [L._('From'), L._('Until')],
 })
 
 L.FormBuilder.FacetSearchDateTime = L.FormBuilder.FacetSearchDate.extend({
-  getInputType: function (type) {
-    return 'datetime-local'
-  },
+  getInputType: (type) => 'datetime-local',
 
   prepareForHTML: function (value) {
     // Value must be in local time
@@ -1020,9 +999,7 @@ L.FormBuilder.DataLayersControl = L.FormBuilder.TernaryChoices.extend({
 })
 
 L.FormBuilder.Range = L.FormBuilder.FloatInput.extend({
-  type: function () {
-    return 'range'
-  },
+  type: () => 'range',
 
   value: function () {
     return L.DomUtil.hasClass(this.wrapper, 'undefined')
@@ -1124,7 +1101,7 @@ U.FormBuilder = L.FormBuilder.extend({
   },
 
   computeDefaultOptions: function () {
-    for (let [key, schema] of Object.entries(U.SCHEMA)) {
+    for (const [key, schema] of Object.entries(U.SCHEMA)) {
       if (schema.type === Boolean) {
         if (schema.nullable) schema.handler = 'NullableChoices'
         else schema.handler = 'Switch'
diff --git a/umap/static/umap/js/umap.icon.js b/umap/static/umap/js/umap.icon.js
index 80198afdc..b79114faa 100644
--- a/umap/static/umap/js/umap.icon.js
+++ b/umap/static/umap/js/umap.icon.js
@@ -17,7 +17,7 @@ U.Icon = L.DivIcon.extend({
     }
   },
 
-  _setRecent: function (url) {
+  _setRecent: (url) => {
     if (U.Utils.hasVar(url)) return
     if (url === U.SCHEMA.iconUrl.default) return
     if (U.Icon.RECENT.indexOf(url) === -1) {
@@ -49,14 +49,10 @@ U.Icon = L.DivIcon.extend({
     return this.map.getDefaultOption('iconOpacity')
   },
 
-  formatUrl: function (url, feature) {
-    return U.Utils.greedyTemplate(
-      url || '',
-      feature ? feature.extendedProperties() : {}
-    )
-  },
+  formatUrl: (url, feature) =>
+    U.Utils.greedyTemplate(url || '', feature ? feature.extendedProperties() : {}),
 
-  onAdd: function () {},
+  onAdd: () => {},
 })
 
 U.Icon.Default = U.Icon.extend({
@@ -208,11 +204,10 @@ U.Icon.Cluster = L.DivIcon.extend({
   },
 })
 
-U.Icon.isImg = function (src) {
-  return U.Utils.isPath(src) || U.Utils.isRemoteUrl(src) || U.Utils.isDataImage(src)
-}
+U.Icon.isImg = (src) =>
+  U.Utils.isPath(src) || U.Utils.isRemoteUrl(src) || U.Utils.isDataImage(src)
 
-U.Icon.makeIconElement = function (src, parent) {
+U.Icon.makeIconElement = (src, parent) => {
   let icon
   if (U.Icon.isImg(src)) {
     icon = L.DomUtil.create('img')
@@ -225,7 +220,7 @@ U.Icon.makeIconElement = function (src, parent) {
   return icon
 }
 
-U.Icon.setIconContrast = function (icon, parent, src, bgcolor) {
+U.Icon.setIconContrast = (icon, parent, src, bgcolor) => {
   /*
    * icon: the element we'll adapt the style, it can be an image or text
    * parent: the element we'll consider to decide whether to adapt the style,
diff --git a/umap/static/umap/js/umap.js b/umap/static/umap/js/umap.js
index 84d567c27..d58c4e57e 100644
--- a/umap/static/umap/js/umap.js
+++ b/umap/static/umap/js/umap.js
@@ -83,18 +83,15 @@ U.Map = L.Map.extend({
     }
 
     let editedFeature = null
-    const self = this
     try {
       Object.defineProperty(this, 'editedFeature', {
-        get: function () {
-          return editedFeature
-        },
-        set: function (feature) {
+        get: () => editedFeature,
+        set: (feature) => {
           if (editedFeature && editedFeature !== feature) {
             editedFeature.endEdit()
           }
           editedFeature = feature
-          self.fire('seteditedfeature')
+          this.fire('seteditedfeature')
         },
       })
     } catch (e) {
@@ -156,9 +153,7 @@ U.Map = L.Map.extend({
     let isDirty = false // self status
     try {
       Object.defineProperty(this, 'isDirty', {
-        get: function () {
-          return isDirty
-        },
+        get: () => isDirty,
         set: function (status) {
           isDirty = status
           this.checkDirty()
@@ -235,9 +230,9 @@ U.Map = L.Map.extend({
   },
 
   render: function (fields) {
-    let impacts = U.Utils.getImpactsFromSchema(fields)
+    const impacts = U.Utils.getImpactsFromSchema(fields)
 
-    for (let impact of impacts) {
+    for (const impact of impacts) {
       switch (impact) {
         case 'ui':
           this.initCaptionBar()
@@ -274,7 +269,7 @@ U.Map = L.Map.extend({
     })
   },
 
-  setOptionsFromQueryString: function (options) {
+  setOptionsFromQueryString: (options) => {
     // This is not an editable option
     L.Util.setFromQueryString(options, 'editMode')
     // FIXME retrocompat
@@ -341,7 +336,7 @@ U.Map = L.Map.extend({
 
   // Merge the given schema with the default one
   // Missing keys inside the schema are merged with the default ones.
-  overrideSchema: function (schema) {
+  overrideSchema: (schema) => {
     for (const [key, extra] of Object.entries(schema)) {
       U.SCHEMA[key] = L.extend({}, U.SCHEMA[key], extra)
     }
@@ -624,7 +619,7 @@ U.Map = L.Map.extend({
   initTileLayers: function () {
     this.tilelayers = []
     for (const props of this.options.tilelayers) {
-      let layer = this.createTileLayer(props)
+      const layer = this.createTileLayer(props)
       this.tilelayers.push(layer)
       if (
         this.options.tilelayer &&
@@ -647,9 +642,7 @@ U.Map = L.Map.extend({
     if (this._controls) this._controls.tilelayers.setLayers()
   },
 
-  createTileLayer: function (tilelayer) {
-    return new L.TileLayer(tilelayer.url_template, tilelayer)
-  },
+  createTileLayer: (tilelayer) => new L.TileLayer(tilelayer.url_template, tilelayer),
 
   selectTileLayer: function (tilelayer) {
     if (tilelayer === this.selected_tilelayer) {
@@ -756,7 +749,7 @@ U.Map = L.Map.extend({
     }
   },
 
-  latLng: function (a, b, c) {
+  latLng: (a, b, c) => {
     // manage geojson case and call original method
     if (!(a instanceof L.LatLng) && a.coordinates) {
       // Guess it's a geojson
@@ -766,10 +759,10 @@ U.Map = L.Map.extend({
   },
 
   handleLimitBounds: function () {
-    const south = parseFloat(this.options.limitBounds.south),
-      west = parseFloat(this.options.limitBounds.west),
-      north = parseFloat(this.options.limitBounds.north),
-      east = parseFloat(this.options.limitBounds.east)
+    const south = Number.parseFloat(this.options.limitBounds.south),
+      west = Number.parseFloat(this.options.limitBounds.west),
+      north = Number.parseFloat(this.options.limitBounds.north),
+      east = Number.parseFloat(this.options.limitBounds.east)
     if (!isNaN(south) && !isNaN(west) && !isNaN(north) && !isNaN(east)) {
       const bounds = L.latLngBounds([
         [south, west],
@@ -815,9 +808,7 @@ U.Map = L.Map.extend({
     datalayer.edit()
   },
 
-  getDefaultOption: function (option) {
-    return U.SCHEMA[option] && U.SCHEMA[option].default
-  },
+  getDefaultOption: (option) => U.SCHEMA[option] && U.SCHEMA[option].default,
 
   getOption: function (option, feature) {
     if (feature) {
@@ -841,11 +832,10 @@ U.Map = L.Map.extend({
   },
 
   updateTileLayers: function () {
-    const self = this,
-      callback = (tilelayer) => {
-        self.options.tilelayer = tilelayer.toJSON()
-        self.isDirty = true
-      }
+    const callback = (tilelayer) => {
+      this.options.tilelayer = tilelayer.toJSON()
+      this.isDirty = true
+    }
     if (this._controls.tilelayersChooser)
       this._controls.tilelayersChooser.openSwitcher({
         callback: callback,
@@ -911,14 +901,13 @@ U.Map = L.Map.extend({
     }
 
     if (importedData.geometry) this.options.center = this.latLng(importedData.geometry)
-    const self = this
     importedData.layers.forEach((geojson) => {
       if (!geojson._umap_options && geojson._storage) {
         geojson._umap_options = geojson._storage
         delete geojson._storage
       }
       delete geojson._umap_options?.id // Never trust an id at this stage
-      const dataLayer = self.createDataLayer(geojson._umap_options)
+      const dataLayer = this.createDataLayer(geojson._umap_options)
       dataLayer.fromUmapGeoJSON(geojson)
     })
 
@@ -936,11 +925,10 @@ U.Map = L.Map.extend({
   importFromFile: function (file) {
     const reader = new FileReader()
     reader.readAsText(file)
-    const self = this
     reader.onload = (e) => {
       const rawData = e.target.result
       try {
-        self.importRaw(rawData)
+        this.importRaw(rawData)
       } catch (e) {
         console.error('Error importing data', e)
         U.Alert.error(L._('Invalid umap data in {filename}', { filename: file.name }))
diff --git a/umap/static/umap/js/umap.layer.js b/umap/static/umap/js/umap.layer.js
index 4ab4462c2..82cbe7dc9 100644
--- a/umap/static/umap/js/umap.layer.js
+++ b/umap/static/umap/js/umap.layer.js
@@ -15,11 +15,9 @@ U.Layer = {
     return this._layers
   },
 
-  getEditableOptions: function () {
-    return []
-  },
+  getEditableOptions: () => [],
 
-  onEdit: function () {},
+  onEdit: () => {},
 
   hasDataVisible: function () {
     return !!Object.keys(this._layers).length
@@ -67,9 +65,7 @@ U.Layer.Cluster = L.MarkerClusterGroup.extend({
       polygonOptions: {
         color: this.datalayer.getColor(),
       },
-      iconCreateFunction: function (cluster) {
-        return new U.Icon.Cluster(datalayer, cluster)
-      },
+      iconCreateFunction: (cluster) => new U.Icon.Cluster(datalayer, cluster),
     }
     if (this.datalayer.options.cluster && this.datalayer.options.cluster.radius) {
       options.maxClusterRadius = this.datalayer.options.cluster.radius
@@ -99,26 +95,24 @@ U.Layer.Cluster = L.MarkerClusterGroup.extend({
     return L.MarkerClusterGroup.prototype.removeLayer.call(this, layer)
   },
 
-  getEditableOptions: function () {
-    return [
-      [
-        'options.cluster.radius',
-        {
-          handler: 'BlurIntInput',
-          placeholder: L._('Clustering radius'),
-          helpText: L._('Override clustering radius (default 80)'),
-        },
-      ],
-      [
-        'options.cluster.textColor',
-        {
-          handler: 'TextColorPicker',
-          placeholder: L._('Auto'),
-          helpText: L._('Text color for the cluster label'),
-        },
-      ],
-    ]
-  },
+  getEditableOptions: () => [
+    [
+      'options.cluster.radius',
+      {
+        handler: 'BlurIntInput',
+        placeholder: L._('Clustering radius'),
+        helpText: L._('Override clustering radius (default 80)'),
+      },
+    ],
+    [
+      'options.cluster.textColor',
+      {
+        handler: 'TextColorPicker',
+        placeholder: L._('Auto'),
+        helpText: L._('Text color for the cluster label'),
+      },
+    ],
+  ],
 
   onEdit: function (field, builder) {
     if (field === 'options.cluster.radius') {
@@ -182,7 +176,7 @@ U.Layer.Choropleth = L.FeatureGroup.extend({
   getValues: function () {
     const values = []
     this.datalayer.eachLayer((layer) => {
-      let value = this._getValue(layer)
+      const value = this._getValue(layer)
       if (!isNaN(value)) values.push(value)
     })
     return values
@@ -370,7 +364,7 @@ U.Layer.Heat = L.HeatLayer.extend({
         this.datalayer.options.heat &&
         this.datalayer.options.heat.intensityProperty
       ) {
-        alt = parseFloat(
+        alt = Number.parseFloat(
           layer.properties[this.datalayer.options.heat.intensityProperty || 0]
         )
         latlng = new L.LatLng(latlng.lat, latlng.lng, alt)
@@ -383,37 +377,33 @@ U.Layer.Heat = L.HeatLayer.extend({
     this.setLatLngs([])
   },
 
-  getFeatures: function () {
-    return {}
-  },
+  getFeatures: () => ({}),
 
   getBounds: function () {
     return L.latLngBounds(this._latlngs)
   },
 
-  getEditableOptions: function () {
-    return [
-      [
-        'options.heat.radius',
-        {
-          handler: 'Range',
-          min: 10,
-          max: 100,
-          step: 5,
-          label: L._('Heatmap radius'),
-          helpText: L._('Override heatmap radius (default 25)'),
-        },
-      ],
-      [
-        'options.heat.intensityProperty',
-        {
-          handler: 'BlurInput',
-          placeholder: L._('Heatmap intensity property'),
-          helpText: L._('Optional intensity property for heatmap'),
-        },
-      ],
-    ]
-  },
+  getEditableOptions: () => [
+    [
+      'options.heat.radius',
+      {
+        handler: 'Range',
+        min: 10,
+        max: 100,
+        step: 5,
+        label: L._('Heatmap radius'),
+        helpText: L._('Override heatmap radius (default 25)'),
+      },
+    ],
+    [
+      'options.heat.intensityProperty',
+      {
+        handler: 'BlurInput',
+        placeholder: L._('Heatmap intensity property'),
+        helpText: L._('Optional intensity property for heatmap'),
+      },
+    ],
+  ],
 
   onEdit: function (field, builder) {
     if (field === 'options.heat.intensityProperty') {
@@ -538,23 +528,20 @@ U.DataLayer = L.Evented.extend({
 
     let isDirty = false
     let isDeleted = false
-    const self = this
     try {
       Object.defineProperty(this, 'isDirty', {
-        get: function () {
-          return isDirty
-        },
-        set: function (status) {
-          if (!isDirty && status) self.fire('dirty')
+        get: () => isDirty,
+        set: (status) => {
+          if (!isDirty && status) this.fire('dirty')
           isDirty = status
           if (status) {
-            self.map.addDirtyDatalayer(self)
+            this.map.addDirtyDatalayer(this)
             // A layer can be made dirty by indirect action (like dragging layers)
             // we need to have it loaded before saving it.
-            if (!self.isLoaded()) self.fetchData()
+            if (!this.isLoaded()) this.fetchData()
           } else {
-            self.map.removeDirtyDatalayer(self)
-            self.isDeleted = false
+            this.map.removeDirtyDatalayer(this)
+            this.isDeleted = false
           }
         },
       })
@@ -563,13 +550,11 @@ U.DataLayer = L.Evented.extend({
     }
     try {
       Object.defineProperty(this, 'isDeleted', {
-        get: function () {
-          return isDeleted
-        },
-        set: function (status) {
-          if (!isDeleted && status) self.fire('deleted')
+        get: () => isDeleted,
+        set: (status) => {
+          if (!isDeleted && status) this.fire('deleted')
           isDeleted = status
-          if (status) self.isDirty = status
+          if (status) this.isDirty = status
         },
       })
     } catch (e) {
@@ -618,9 +603,9 @@ U.DataLayer = L.Evented.extend({
   },
 
   render: function (fields, builder) {
-    let impacts = U.Utils.getImpactsFromSchema(fields)
+    const impacts = U.Utils.getImpactsFromSchema(fields)
 
-    for (let impact of impacts) {
+    for (const impact of impacts) {
       switch (impact) {
         case 'ui':
           this.map.onDataLayersChanged()
@@ -787,8 +772,8 @@ U.DataLayer = L.Evented.extend({
   },
 
   showAtZoom: function () {
-    const from = parseInt(this.options.fromZoom, 10),
-      to = parseInt(this.options.toZoom, 10),
+    const from = Number.parseInt(this.options.fromZoom, 10),
+      to = Number.parseInt(this.options.toZoom, 10),
       zoom = this.map.getZoom()
     return !((!isNaN(from) && zoom < from) || (!isNaN(to) && zoom > to))
   },
@@ -953,7 +938,7 @@ U.DataLayer = L.Evented.extend({
     this.rawToGeoJSON(c, type, (geojson) => this.addData(geojson))
   },
 
-  rawToGeoJSON: function (c, type, callback) {
+  rawToGeoJSON: (c, type, callback) => {
     const toDom = (x) => {
       const doc = new DOMParser().parseFromString(x, 'text/xml')
       const errorNode = doc.querySelector('parsererror')
@@ -1045,7 +1030,7 @@ U.DataLayer = L.Evented.extend({
 
     const geometry = geojson.type === 'Feature' ? geojson.geometry : geojson
 
-    let feature = this.geoJSONToLeaflet({ geometry, geojson })
+    const feature = this.geoJSONToLeaflet({ geometry, geojson })
     if (feature) {
       this.addLayer(feature)
       feature.onCommit()
@@ -1318,7 +1303,7 @@ U.DataLayer = L.Evented.extend({
       layerProperties.appendChild(builder.build())
     }
 
-    let shapeOptions = [
+    const shapeOptions = [
       'options.color',
       'options.iconClass',
       'options.iconUrl',
@@ -1337,7 +1322,7 @@ U.DataLayer = L.Evented.extend({
     const shapeProperties = L.DomUtil.createFieldset(container, L._('Shape properties'))
     shapeProperties.appendChild(builder.build())
 
-    let optionsFields = [
+    const optionsFields = [
       'options.smoothFactor',
       'options.dashArray',
       'options.zoomTo',
@@ -1499,8 +1484,8 @@ U.DataLayer = L.Evented.extend({
 
   buildVersionsFieldset: async function (container) {
     const appendVersion = (data) => {
-      const date = new Date(parseInt(data.at, 10))
-      const content = `${date.toLocaleString(L.lang)} (${parseInt(data.size) / 1000}Kb)`
+      const date = new Date(Number.parseInt(data.at, 10))
+      const content = `${date.toLocaleString(L.lang)} (${Number.parseInt(data.size) / 1000}Kb)`
       const el = L.DomUtil.create('div', 'umap-datalayer-version', versionsContainer)
       const button = L.DomUtil.createButton(
         '',
diff --git a/umap/static/umap/js/umap.permissions.js b/umap/static/umap/js/umap.permissions.js
index d10bdbfe1..86da5a590 100644
--- a/umap/static/umap/js/umap.permissions.js
+++ b/umap/static/umap/js/umap.permissions.js
@@ -12,16 +12,13 @@ U.MapPermissions = L.Class.extend({
     this.setOptions(map.options.permissions)
     this.map = map
     let isDirty = false
-    const self = this
     try {
       Object.defineProperty(this, 'isDirty', {
-        get: function () {
-          return isDirty
-        },
-        set: function (status) {
+        get: () => isDirty,
+        set: (status) => {
           isDirty = status
           if (status) {
-            self.map.isDirty = status
+            this.map.isDirty = status
           }
         },
       })
diff --git a/umap/static/umap/js/umap.popup.js b/umap/static/umap/js/umap.popup.js
index e666d5b9e..2912f169d 100644
--- a/umap/static/umap/js/umap.popup.js
+++ b/umap/static/umap/js/umap.popup.js
@@ -84,11 +84,11 @@ U.Popup.Panel = U.Popup.extend({
     }
   },
 
-  update: function () {},
-  _updateLayout: function () {},
-  _updatePosition: function () {},
-  _adjustPan: function () {},
-  _animateZoom: function () {},
+  update: () => {},
+  _updateLayout: () => {},
+  _updatePosition: () => {},
+  _adjustPan: () => {},
+  _animateZoom: () => {},
 })
 U.Popup.SimplePanel = U.Popup.Panel // Retrocompat.
 
@@ -102,7 +102,7 @@ U.PopupTemplate.Default = L.Class.extend({
     this.container = container
   },
 
-  renderTitle: function () {},
+  renderTitle: () => {},
 
   renderBody: function () {
     const template = this.feature.getOption('popupContentTemplate')
@@ -181,7 +181,7 @@ U.PopupTemplate.BaseWithTitle = U.PopupTemplate.Default.extend({
 })
 
 U.PopupTemplate.Table = U.PopupTemplate.BaseWithTitle.extend({
-  formatRow: function (key, value) {
+  formatRow: (key, value) => {
     if (value.indexOf('http') === 0) {
       value = `<a href="${value}" target="_blank">${value}</a>`
     }
@@ -268,7 +268,7 @@ U.PopupTemplate.OSM = U.PopupTemplate.Default.extend({
     const color = this.feature.getDynamicOption('color')
     title.style.backgroundColor = color
     const iconUrl = this.feature.getDynamicOption('iconUrl')
-    let icon = U.Icon.makeIconElement(iconUrl, title)
+    const icon = U.Icon.makeIconElement(iconUrl, title)
     L.DomUtil.addClass(icon, 'icon')
     U.Icon.setIconContrast(icon, title, iconUrl, color)
     if (L.DomUtil.contrastedColor(title, color)) title.style.color = 'white'
diff --git a/umap/static/umap/js/umap.share.js b/umap/static/umap/js/umap.share.js
index 459183ac4..dbd68710e 100644
--- a/umap/static/umap/js/umap.share.js
+++ b/umap/static/umap/js/umap.share.js
@@ -1,28 +1,22 @@
 U.Share = L.Class.extend({
   EXPORT_TYPES: {
     geojson: {
-      formatter: function (map) {
-        return JSON.stringify(map.toGeoJSON(), null, 2)
-      },
+      formatter: (map) => JSON.stringify(map.toGeoJSON(), null, 2),
       ext: '.geojson',
       filetype: 'application/json',
     },
     gpx: {
-      formatter: function (map) {
-        return togpx(map.toGeoJSON())
-      },
+      formatter: (map) => togpx(map.toGeoJSON()),
       ext: '.gpx',
       filetype: 'application/gpx+xml',
     },
     kml: {
-      formatter: function (map) {
-        return tokml(map.toGeoJSON())
-      },
+      formatter: (map) => tokml(map.toGeoJSON()),
       ext: '.kml',
       filetype: 'application/vnd.google-earth.kml+xml',
     },
     csv: {
-      formatter: function (map) {
+      formatter: (map) => {
         const table = []
         map.eachFeature((feature) => {
           const row = feature.toGeoJSON()['properties'],
diff --git a/umap/static/umap/js/umap.slideshow.js b/umap/static/umap/js/umap.slideshow.js
index 6b1d13a84..54117a9e6 100644
--- a/umap/static/umap/js/umap.slideshow.js
+++ b/umap/static/umap/js/umap.slideshow.js
@@ -15,8 +15,6 @@ U.Slideshow = L.Class.extend({
 
     // current feature
     let current = null
-
-    const self = this
     try {
       Object.defineProperty(this, 'current', {
         get: function () {
@@ -26,7 +24,7 @@ U.Slideshow = L.Class.extend({
           }
           return current
         },
-        set: function (feature) {
+        set: (feature) => {
           current = feature
         },
       })
@@ -35,9 +33,9 @@ U.Slideshow = L.Class.extend({
     }
     try {
       Object.defineProperty(this, 'next', {
-        get: function () {
+        get: () => {
           if (!current) {
-            return self.current
+            return this.current
           }
           return current.getNext()
         },
@@ -69,7 +67,7 @@ U.Slideshow = L.Class.extend({
   },
 
   timeSpinner: function () {
-    const time = parseInt(this.options.delay, 10)
+    const time = Number.parseInt(this.options.delay, 10)
     if (!time) return
     const css = `rotation ${time / 1000}s infinite linear`,
       spinners = document.querySelectorAll('.umap-slideshow-toolbox .play .spinner')
@@ -81,7 +79,7 @@ U.Slideshow = L.Class.extend({
     }
   },
 
-  resetSpinners: function () {
+  resetSpinners: () => {
     // Make that animnation is coordinated with user actions
     const spinners = document.querySelectorAll('.umap-slideshow-toolbox .play .spinner')
 
diff --git a/umap/static/umap/js/umap.tableeditor.js b/umap/static/umap/js/umap.tableeditor.js
index 5cbaa034f..021815c4c 100644
--- a/umap/static/umap/js/umap.tableeditor.js
+++ b/umap/static/umap/js/umap.tableeditor.js
@@ -81,7 +81,7 @@ U.TableEditor = L.Class.extend({
     this.properties = this.datalayer._propertiesIndex
   },
 
-  validateName: function (name) {
+  validateName: (name) => {
     if (name.indexOf('.') !== -1) {
       U.Alert.error(L._('Invalide property name: {name}', { name: name }))
       return false