10 KiB
Twitter Emoji (Twemoji) 
A simple library that provides standard Unicode emoji support across all platforms.
CDN Support
The folks over at MaxCDN graciously provide CDN support.
Just use the following in the <head> tag of your HTML document(s):
<script src="//twemoji.maxcdn.com/twemoji.min.js"></script>
API
Following all methods exposed through the twemoji namespace.
twemoji.parse( ... )
This is the main parsing utility and has 3 overloads per each parsing type.
There are mainly two kind of parsing: string parsing and DOM parsing.
Each of them accept a callback to generate each image source or an options object with parsing info.
Here is a walk through all parsing possibilities:
string parsing
Given a generic string, it will replace all emoji with an <img> tag.
While this can be used to inject via innerHTML emoji image tags, 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, this will not be converted into <script> since it's out of this method 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 src attribute will be the one returned by the same 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 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
Differently from string parsing, if the first argument is a HTMLElement generated image tags will replace emoji that are inside #text node only without compromising surrounding nodes or listeners, and avoiding completely the usage of innerHTML.
If security is a major concern, this parsing can be considered the safest option but with a slightly penalized performance gap due DOM operations that are inevitably costy compared to basic strings.
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 exactly same way for DOM parsing.
Object as parameter
Here the list of properties accepted by the optional object that could be passed to parse.
{
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 images src.
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 per each generated image is emoji. It is possible to specify a different one through this property.
size
The default assets 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 there is no need to specify a size. It is possible to chose a folder, as is 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 one.
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 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);
}
});
Build
In order to build the Unicode based standard emoji RegExp, probably the most important core feature of this library, the twemoji-generator.js file needs to perform few online and offline operations.
Once executed through node twemoji-generator.js, and after installing via npm install dependencies, this file will create a fresh new copy of all libraries.
This means that if you'd like to change or improve twemoji, you should probably do it inside the createTwemoji function at the bottom of twemoji-generator.js instead of directly in the library, unless it's not just for testing purpose.
Future Plans: Unicode 8.0 and Diversity
The twemoji project currently adheres to the 7.0 Unicode version and supports 872 different emoji. In the future, we hope to work with the community to support Unicode 8.0 additions like Diversity.
Attribution Requirements
As an open source project, attribution is critical from a legal, practical and motivational perspective in our opinion. The graphics are licensed under the CC-BY 4.0 which has a pretty good guide on best practices for attribution.
However, we consider the guide a bit onerous and as a project, will accept a mention in a project README or an 'About' section or footer on a website. In mobile applications, a common place would be in the Settings/About section (for example, see the mobile Twitter application Settings->About->Legal section). We would consider a mention in the HTML/JS source sufficient also.
Community Projects
- Twemoji Awesome by @ellekasai: Use Twemoji using CSS classes (like Font Awesome)
Committers and Contributors
- Andrea Giammarchi (Twitter)
- Chris Aniszczyk (Twitter)
- Tom Wuttke (Twitter)
- Joen Asmussen (WordPress)
- Marcus Kazmierczak (WordPress)
The goal of this project is to simply provide emoji for everyone. We definitely welcome improvements and fixes, but we may not merge every pull request suggested by the community due to the simple nature of the project.
The rules for contributing are available at CONTRIBUTING.md file.
Thank you to all of our contributors.
License
Copyright 2014 Twitter, Inc and other contributors
Code licensed under the MIT License: http://opensource.org/licenses/MIT
Graphics licensed under CC-BY 4.0: https://creativecommons.org/licenses/by/4.0/