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html2amp

  • CircleCI
  • node

html2amp is simple converter from HTML into AMP(Accelerated Mobile Pages).

Motivation

This library allow you to convert simple html into AMP. What does the simple mean ? As you know AMP has many restrictions to make it such as ...

  • Some html tags are needed to be replaced by special one (<amp-img />, <amp-iframe />)
  • CSS should be less than 50,000 bytes and it should be as inline

You can see full Specification here. AMP HTML Specification It could be hard to convert any html into AMP perfectly but if it's simple one it's possible to convert automatically.

For example...

  • Tech blog
  • Corporate news blog

So this library's target is To convert simple html into AMP.

Installation

$ npm install html2amp --save

Usage

const html2amp = require('html2amp')
const html = `<your html>`
const options = {}
const amp = html2amp(html, options)

console.log(amp) // amp string

Options

name default value note
cwd . image / styles base path
gaConfigPath amp-analytics config json path for google analytics
serviceWorker attributes of amp-install-serviceworker
e.g. src, data-iframe-src
optimize false if true, this module will optimize the html by using @ampproject/toolbox-optimizer
cssPlugins [] you can add custom converter for css.
htmlPlugins [] you can add custom converter for css.

CSS Plugin

CSS Plugin allow you to add custom converter for CSS.

/**
 * elementString :
 *   e.g. '<style id="test">.test { color: red; }</style>'
 *   e.g. '<link rel="stylesheet" href="http://example.com/test.css"></style>'
 * cssText :
 *   e.g. '.test{ color: red; }'
 * options : module options
 **/
const plugin = (elementString, cssText, options) => {
  // you need to return cssText which you modified.
  return cssText.replace('red', '#ccc')
}

// options
const options = {
  cssPlugins: [ plugin ]
}

HTMl Plugin

HTML Plugin allow you to add custom converter for HTML.

/**
 * htmlString :
 *   e.g. '<html><body><h1>Normal HTML</h1></body></html>'
 * options : module options
 **/
const plugin = (htmlString, options) => {
  // you need to return htmlString which you modified.
  return htmlString.replace('Normal', 'AMP')
}

// options
const options = {
  htmlPlugins: [ plugin ]
}

Functions

This library ...

  • add <meta charset="utf-8" /> if it does not exist
  • add amp attribute to the <html>
  • add viewport meta if it does not exist
    • viewport should be <meta name="viewport" content="width=device-width,minimum-scale=1,initial-scale=1">
  • replace all external css files with one <style amp-custom>/* css is here */<style/>
    • also removed !imporant keyword
  • remove all scripts
  • add AMP CSS boilerplate
  • replace <img />, <picture><source /></picture> with <amp-img />
    • also add width height attributes if it do not exist
    • also add layout="responsive" attribute
  • replace <iframe /> with <amp-iframe />
  • add <amp-analytics />
    • only support google analytics
    • also removed regular google analytics tag
    • it's optional
  • add amp-install-serviceworker
    • it's optional
  • replace all a tag links which destination is original site with absolute url which starts with http[s]
    • original url comes from canonical's href attribute
    • e.g. <a href="/test"> is replaced with <a href="https//original-url.com/test">
    • NOTE: If the canonical url in your html is not absolute url this function would be passed
  • remove all <link ref="preload" type="script">, <link ref="preload" type="fetch">
  • optimize html by using @ampproject/toolbox-optimizer

Preparation

To make your html valid AMP your html also should ...

  • have canonical meta tag to regular HTML
  • Don't have any problem if all scripts are removed
  • Don't have any problem if all !imporant syntax are removed in css