Use ESM

Author: wooorm

.gitignore

@@ -1,8 +1,5 @@
 .DS_Store
 *.log
-.nyc_output/
 coverage/
 node_modules/
-unherit.js
-unherit.min.js
 yarn.lock

.prettierignore

@@ -1,5 +1,2 @@
 coverage/
-unherit.js
-unherit.min.js
-*.json
 *.md

index.js

@@ -1,28 +1,25 @@
-'use strict'
-
-var xtend = require('xtend')
-var inherits = require('inherits')
-
-module.exports = unherit
+import inherits from 'inherits'
 
 // Create a custom constructor which can be modified without affecting the
 // original class.
-function unherit(Super) {
-  var result
+export function unherit(Super) {
+  var proto
   var key
   var value
 
   inherits(Of, Super)
   inherits(From, Of)
 
   // Clone values.
-  result = Of.prototype
+  proto = Of.prototype
 
-  for (key in result) {
-    value = result[key]
+  // We specifically want to get *all* fields, not just own fields.
+  // eslint-disable-next-line guard-for-in
+  for (key in proto) {
+    value = proto[key]
 
     if (value && typeof value === 'object') {
-      result[key] = 'concat' in value ? value.concat() : xtend(value)
+      proto[key] = 'concat' in value ? value.concat() : Object.assign({}, value)
     }
   }
 
@@ -36,10 +33,8 @@ function unherit(Super) {
 
   // Constructor accepting variadic arguments.
   function Of() {
-    if (!(this instanceof Of)) {
-      return new From(arguments)
-    }
-
-    return Super.apply(this, arguments)
+    return this instanceof Of
+      ? Super.apply(this, arguments)
+      : new From(arguments)
   }
 }

package.json

@@ -19,31 +19,28 @@
   "contributors": [
     "Titus Wormer <[email protected]> (https://wooorm.com)"
   ],
+  "sideEffects": false,
+  "type": "module",
+  "main": "index.js",
   "files": [
     "index.js"
   ],
   "dependencies": {
-    "inherits": "^2.0.0",
-    "xtend": "^4.0.0"
+    "inherits": "^2.0.0"
   },
   "devDependencies": {
-    "browserify": "^17.0.0",
-    "nyc": "^15.0.0",
+    "c8": "^7.0.0",
     "prettier": "^2.0.0",
     "remark-cli": "^9.0.0",
     "remark-preset-wooorm": "^8.0.0",
     "tape": "^5.0.0",
-    "tinyify": "^3.0.0",
     "xo": "^0.38.0"
   },
   "scripts": {
     "format": "remark . -qfo && prettier . -w --loglevel warn && xo --fix",
-    "build-bundle": "browserify . -s unherit -o unherit.js",
-    "build-mangle": "browserify . -s unherit -p tinyify -o unherit.min.js",
-    "build": "npm run build-bundle && npm run build-mangle",
     "test-api": "node test",
-    "test-coverage": "nyc --reporter lcov tape test.js",
-    "test": "npm run format && npm run build && npm run test-coverage"
+    "test-coverage": "c8 --check-coverage --branches 100 --functions 100 --lines 100 --statements 100 --reporter lcov node test.js",
+    "test": "npm run format && npm run test-coverage"
   },
   "prettier": {
     "tabWidth": 2,
@@ -55,14 +52,11 @@
   },
   "xo": {
     "prettier": true,
-    "esnext": false,
     "rules": {
-      "unicorn/prefer-reflect-apply": "off",
-      "guard-for-in": "off"
-    },
-    "ignores": [
-      "unherit.js"
-    ]
+      "no-var": "off",
+      "prefer-arrow-callback": "off",
+      "unicorn/prefer-reflect-apply": "off"
+    }
   },
   "remarkConfig": {
     "plugins": [

readme.md

@@ -10,6 +10,9 @@ class.
 
 ## Install
 
+This package is ESM only: Node 12+ is needed to use it and it must be `import`ed
+instead of `require`d.
+
 [npm][]:
 
 ```sh
@@ -19,8 +22,8 @@ npm install unherit
 ## Use
 
 ```js
-var EventEmitter = require('events').EventEmitter
-var unherit = require('unherit')
+import {EventEmitter} from 'events'
+import {unherit} from 'unherit'
 
 // Create a private class which acts just like `EventEmitter`.
 var Emitter = unherit(EventEmitter)
@@ -36,19 +39,13 @@ new Emitter() instanceof EventEmitter // => true
 
 ## API
 
-### `unherit(Super)`
-
-Create a custom constructor which can be modified without affecting the original
-class.
-
-###### Parameters
+This package exports the following identifiers: `unherit`.
+There is no default export.
 
-*   `Super` (`Function`) — Super-class
-
-###### Returns
+### `unherit(Super)`
 
-`Function` — Constructor acting like `Super`, which can be modified without
-affecting the original class.
+Create a custom constructor (`Function`) from `Super` (`Function`) which can be
+modified without affecting the original class.
 
 ## License
 

test.js

@@ -1,8 +1,6 @@
-'use strict'
-
-var EventEmitter = require('events').EventEmitter
-var test = require('tape')
-var unherit = require('.')
+import {EventEmitter} from 'events'
+import test from 'tape'
+import {unherit} from './index.js'
 
 test('unherit(Super)', function (t) {
   var Emitter = unherit(EventEmitter)
@@ -59,6 +57,7 @@ test('unherit(Super)', function (t) {
 
   D.prototype = new Proto()
   D.prototype.values = [1, 2, 3]
+  D.prototype.object = {a: true}
 
   E = unherit(D)
 
@@ -74,8 +73,10 @@ test('unherit(Super)', function (t) {
 
   F = unherit(D)
 
-  t.deepEqual(F.prototype.values, [1, 2, 3], 'shouldn clone values (1)')
-  t.deepEqual(new F().values, [1, 2, 3], 'shouldn clone values (2)')
+  t.deepEqual(F.prototype.values, [1, 2, 3], 'should clone values (1)')
+  t.deepEqual(new F().values, [1, 2, 3], 'should clone values (2)')
+
+  t.deepEqual(new F().object, {a: true}, 'should clone values (3)')
 
   t.end()
 })