twemoji/LEGACY.md

Twemoji Legacy API (V1)

Usage

CDN Support

Previously, MaxCDN provided support for V1 of the Twemoji API. MaxCDN shut down on December 31, 2022.

Support for V1 of the Twemoji API is no longer available and is not planned. Please migrate to V2.

The rest of this README is kept around for historical purposes and may not work as described.

Download

If instead you want to download a specific version, please look at the gh-pages branch, where you will find the built assets for our legacy versions.

API

Following are all the methods exposed in the twemoji namespace.

twemoji.parse( ... )

This is the main parsing utility and has 3 overloads per parsing type.

There are mainly two kinds of parsing: string parsing and DOM parsing.

Each of them accepts a callback to generate an image source or an options object with parsing info.

Here is a walkthrough of all parsing possibilities:

string parsing

Given a generic string, replaces all emoji with an <img> tag.

While this can be used to inject emoji via image tags in innerHTML, please note that this method does not sanitize the string or prevent malicious code from being executed. As an example, if the text contains a <script> tag, it will not be converted into <script> since it's out of this method's scope to prevent these kind of attacks.

However, for already sanitized strings, this method can be considered safe enough. Please see DOM parsing if security is one of your major concerns.

twemoji.parse('I \u2764\uFE0F emoji!');

// will produce
/*
I <img
  class="emoji"
  draggable="false"
  alt="❤️"
  src="https://twemoji.maxcdn.com/36x36/2764.png"/> emoji!
*/

string parsing + callback

If a callback is passed, the value of the src attribute will be the value returned by the callback.

twemoji.parse(
  'I \u2764\uFE0F emoji!',
  function(icon, options, variant) {
    return '/assets/' + options.size + '/' + icon + '.gif';
  }
);

// will produce
/*
I <img
  class="emoji"
  draggable="false"
  alt="❤️"
  src="/assets/36x36/2764.gif"/> emoji!
*/

By default, the options.size parameter will be the string "36x36" and the variant will be an optional \uFE0F char that is usually ignored by default. If your assets include or distinguish between \u2764\uFE0F and \u2764, you might want to use such a variable.

string parsing + callback returning falsy

If the callback returns "falsy values" such as null, undefined, 0, false, or an empty string, nothing will change for that specific emoji.

var i = 0;
twemoji.parse(
  'emoji, m\u2764\uFE0Fn am\u2764\uFE0Fur',
  function(icon, options, variant) {
    if (i++ === 0) {
      return; // no changes made first call
    }
    return '/assets/' + icon + options.ext;
  }
);

// will produce
/*
emoji, m❤️n am<img
  class="emoji"
  draggable="false"
  alt="❤️"
  src="/assets/2764.png"/>ur
*/

string parsing + object

In case an object is passed as second parameter, the passed options object will reflect its properties.

twemoji.parse(
  'I \u2764\uFE0F emoji!',
  {
    callback: function(icon, options) {
      return '/assets/' + options.size + '/' + icon + '.gif';
    },
    size: 128
  }
);

// will produce
/*
I <img
  class="emoji"
  draggable="false"
  alt="❤️"
  src="/assets/128x128/2764.gif"/> emoji!
*/

DOM parsing

In contrast to string parsing, if the first argument is an HTMLElement, generated image tags will replace emoji that are inside #text nodes only without compromising surrounding nodes or listeners, and completely avoiding the usage of innerHTML.

If security is a major concern, this parsing can be considered the safest option but with a slight performance penalty due to DOM operations that are inevitably costly.

var div = document.createElement('div');
div.textContent = 'I \u2764\uFE0F emoji!';
document.body.appendChild(div);

twemoji.parse(document.body);

var img = div.querySelector('img');

// note the div is preserved
img.parentNode === div; // true

img.src;        // https://twemoji.maxcdn.com/36x36/2764.png
img.alt;        // \u2764\uFE0F
img.className;  // emoji
img.draggable;  // false

All other overloads described for string are available in exactly the same way for DOM parsing.

Object as parameter

Here's the list of properties accepted by the optional object that can be passed to the parse function.

  {
    callback: Function,   // default the common replacer
    attributes: Function, // default returns {}
    base: string,         // default MaxCDN
    ext: string,          // default ".png"
    className: string,    // default "emoji"
    size: string|number,  // default "36x36"
    folder: string        // in case it's specified
                          // it replaces .size info, if any
  }

callback

The function to invoke in order to generate image src(s).

By default it is a function like the following one:

function imageSourceGenerator(icon, options) {
  return ''.concat(
    options.base, // by default Twitter Inc. CDN
    options.size, // by default "36x36" string
    '/',
    icon,         // the found emoji as code point
    options.ext   // by default ".png"
  );
}

attributes

The function to invoke in order to generate additional, custom attributes for the image tag.

By default it is a function like the following one:

function attributesCallback(icon, variant) {
  return {
    title: 'Emoji: ' + icon + variant
  };
}

Event handlers cannot be specified via this method, and twemoji-provided attributes (src, alt, className, draggable) cannot be re-defined.

base

The default url is the same as twemoji.base, so if you modify the former, it will reflect as default for all parsed strings or nodes.

ext

The default image extension is the same as twemoji.ext which is ".png".

If you modify the former, it will reflect as default for all parsed strings or nodes.

className

The default class for each generated image is emoji. It is possible to specify a different one through this property.

size

The default asset size is the same as twemoji.size which is "36x36".

If you modify the former, it will reflect as default for all parsed strings or nodes.

folder

In case you don't want to specify a size for the image. It is possible to choose a folder, as in the case of SVG emoji.

twemoji.parse(genericNode, {
  folder: 'svg',
  ext: '.svg'
});

This will generate urls such https://twemoji.maxcdn.com/svg/2764.svg instead of using a specific size based image.

Utilities

Basic utilities / helpers to convert code points to JavaScript surrogates and vice versa.

twemoji.convert.fromCodePoint()

For a given HEX codepoint, returns UTF-16 surrogate pairs.

twemoji.convert.fromCodePoint('1f1e8');
 // "\ud83c\udde8"

twemoji.convert.toCodePoint()

For given UTF-16 surrogate pairs, returns the equivalent HEX codepoint.

 twemoji.convert.toCodePoint('\ud83c\udde8\ud83c\uddf3');
 // "1f1e8-1f1f3"

 twemoji.convert.toCodePoint('\ud83c\udde8\ud83c\uddf3', '~');
 // "1f1e8~1f1f3"

Tips

Inline Styles

If you'd like to size the emoji according to the surrounding text, you can add the following CSS to your stylesheet:

img.emoji {
   height: 1em;
   width: 1em;
   margin: 0 .05em 0 .1em;
   vertical-align: -0.1em;
}

This will make sure emoji derive their width and height from the font-size of the text they're shown with. It also adds just a little bit of space before and after each emoji, and pulls them upwards a little bit for better optical alignment.

UTF-8 Character Set

To properly support emoji, the document character set must be set to UTF-8. This can done by including the following meta tag in the document <head>

<meta charset="utf-8">

Exclude Characters

To exclude certain characters from being replaced by twemoji.js, call twemoji.parse() with a callback, returning false for the specific unicode icon. For example:

twemoji.parse(document.body, {
    callback: function(icon, options, variant) {
        switch ( icon ) {
            case 'a9':      // © copyright
            case 'ae':      // ® registered trademark
            case '2122':    // ™ trademark
                return false;
        }
        return ''.concat(options.base, options.size, '/', icon, options.ext);
    }
});

Breaking changes in V2

TL;DR: there's no variant anymore, all callbacks receive the transformed iconId and in some cases the rawText too.

There are a few potentially breaking changes in twemoji version 2:

• the parse invoked function signature is now (iconId, options) instead of (icon, options, variant)
• the attributes function now receives (rawText, iconId) instead of (icon, variant)
• the default remote protocol is now https regardless of whether the current site is http or even file
• the default PNG icon size is 72 pixels and there are no other PNG assets for 16 or 32.
• in order to access latest assets you need to specify folder 2/72x72 or 2/svg.

Everything else is pretty much the same, so if you were using the defaults, all you need to do is to add the version 2/ before the twemoji.js file you were using.