360 lines
13 KiB
Markdown
360 lines
13 KiB
Markdown
# Twitter Emoji (Twemoji) [![Build Status](https://travis-ci.org/twitter/twemoji.svg?branch=gh-pages)](https://travis-ci.org/twitter/twemoji)
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A simple library that provides standard Unicode [emoji](http://en.wikipedia.org/wiki/Emoji) support across all platforms.
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**Twemoji v2.2** adheres to the [Unicode 9.0 spec](http://unicode.org/versions/Unicode9.0.0/) and supports the [Emoji 4.0 draft spec](http://www.unicode.org/reports/tr51/tr51-8.html) (codepoints and supported emoji are subject to change until the Emoji 4.0 spec is ratified).
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The Twemoji library offers support for **2,477** emojis, including skin tone and gender modifiers.
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## CDN Support
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The folks over at [MaxCDN](https://www.maxcdn.com) have graciously provided CDN support.
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Use the following in the `<head>` tag of your HTML document(s):
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```html
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<script src="//twemoji.maxcdn.com/2/twemoji.min.js?2.2.3"></script>
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```
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## Breaking changes in V2
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_TL;DR_: there's no `variant` anymore, all callbacks receive the transformed `iconId` and in some cases the rawText too.
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There are a few potentially breaking changes in `twemoji` version 2:
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* the `parse` invoked function signature is now `(iconId, options)` instead of `(icon, options, variant)`
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* the `attributes` function now receives `(rawText, iconId)` instead of `(icon, variant)`
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* the **default** remote protocol is now **https** regardless of whether the current site is _http_ or even _file_
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* the **default** PNG icon size is **72** pixels and **there are no other PNG assets** for 16 or 32.
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* in order to access latest assets you need to specify *folder* `2/72x72` or `2/svg`.
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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.
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## API
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Following are all the methods exposed in the `twemoji` namespace.
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### twemoji.parse( ... ) V1
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This is the main parsing utility and has 3 overloads per parsing type.
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There are mainly two kinds of parsing: [string parsing](https://github.com/twitter/twemoji#string-parsing) and [DOM parsing](https://github.com/twitter/twemoji#dom-parsing).
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Each of them accepts a callback to generate an image source or an options object with parsing info.
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Here is a walkthrough of all parsing possibilities:
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##### string parsing (V1)
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Given a generic string, replaces all emoji with an `<img>` tag.
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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.
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However, for already sanitized strings, this method can be considered safe enough. Please see DOM parsing if security is one of your major concerns.
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```js
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twemoji.parse('I \u2764\uFE0F emoji!');
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// will produce
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/*
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I <img
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class="emoji"
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draggable="false"
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alt="❤️"
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src="https://twemoji.maxcdn.com/36x36/2764.png"> emoji!
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*/
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```
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_string parsing + callback_
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If a callback is passed, the value of the `src` attribute will be the value returned by the callback.
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```js
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twemoji.parse(
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'I \u2764\uFE0F emoji!',
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function(icon, options, variant) {
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return '/assets/' + options.size + '/' + icon + '.gif';
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}
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);
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// will produce
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/*
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I <img
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class="emoji"
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draggable="false"
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alt="❤️"
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src="/assets/36x36/2764.gif"> emoji!
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*/
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```
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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.
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_string parsing + callback returning_ `falsy`
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If the callback returns "falsy values" such as `null`, `undefined`, `0`, `false`, or an empty string, nothing will change for that specific emoji.
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```js
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var i = 0;
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twemoji.parse(
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'emoji, m\u2764\uFE0Fn am\u2764\uFE0Fur',
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function(icon, options, variant) {
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if (i++ === 0) {
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return; // no changes made first call
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}
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return '/assets/' + icon + options.ext;
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}
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);
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// will produce
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/*
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emoji, m❤️n am<img
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class="emoji"
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draggable="false"
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alt="❤️"
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src="/assets/2764.png">ur
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*/
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```
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_string parsing + object_
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In case an object is passed as second parameter, the passed `options` object will reflect its properties.
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```js
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twemoji.parse(
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'I \u2764\uFE0F emoji!',
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{
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callback: function(icon, options) {
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return '/assets/' + options.size + '/' + icon + '.gif';
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},
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size: 128
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}
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);
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// will produce
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/*
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I <img
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class="emoji"
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draggable="false"
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alt="❤️"
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src="/assets/128x128/2764.gif"> emoji!
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*/
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```
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##### DOM parsing
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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`.
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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*.
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```js
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var div = document.createElement('div');
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div.textContent = 'I \u2764\uFE0F emoji!';
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document.body.appendChild(div);
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twemoji.parse(document.body);
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var img = div.querySelector('img');
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// note the div is preserved
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img.parentNode === div; // true
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img.src; // https://twemoji.maxcdn.com/36x36/2764.png
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img.alt; // \u2764\uFE0F
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img.className; // emoji
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img.draggable; // false
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```
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All other overloads described for `string` are available in exactly the same way for DOM parsing.
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### Object as parameter
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Here's the list of properties accepted by the optional object that can be passed to the `parse` function.
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```js
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{
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callback: Function, // default the common replacer
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attributes: Function, // default returns {}
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base: string, // default MaxCDN
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ext: string, // default ".png"
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className: string, // default "emoji"
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size: string|number, // default "36x36"
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folder: string // in case it's specified
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// it replaces .size info, if any
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}
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```
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##### callback
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The function to invoke in order to generate image `src`(s).
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By default it is a function like the following one:
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```js
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function imageSourceGenerator(icon, options) {
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return ''.concat(
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options.base, // by default Twitter Inc. CDN
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options.size, // by default "36x36" string
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'/',
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icon, // the found emoji as code point
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options.ext // by default ".png"
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);
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}
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```
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##### attributes (V1)
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The function to invoke in order to generate additional, custom attributes for the image tag.
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By default it is a function like the following one:
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```js
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function attributesCallback(icon, variant) {
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return {
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title: 'Emoji: ' + icon + variant
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};
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}
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```
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Event handlers cannot be specified via this method, and twemoji-provided attributes (src, alt, className, draggable) cannot be re-defined.
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##### base
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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.
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##### ext
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The default image extension is the same as `twemoji.ext` which is `".png"`.
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If you modify the former, it will reflect as default for all parsed strings or nodes.
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##### className
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The default `class` for each generated image is `emoji`. It is possible to specify a different one through this property.
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##### size
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The default asset size is the same as `twemoji.size` which is `"36x36"`.
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If you modify the former, it will reflect as default for all parsed strings or nodes.
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##### folder
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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.
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```js
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twemoji.parse(genericNode, {
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folder: 'svg',
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ext: '.svg'
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});
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```
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This will generate urls such `https://twemoji.maxcdn.com/svg/2764.svg` instead of using a specific size based image.
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## Utilities
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Basic utilities / helpers to convert code points to JavaScript surrogates and vice versa.
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#### twemoji.convert.fromCodePoint()
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For a given HEX codepoint, returns UTF-16 surrogate pairs.
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```js
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twemoji.convert.fromCodePoint('1f1e8');
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// "\ud83c\udde8"
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```
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#### twemoji.convert.toCodePoint()
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For given UTF-16 surrogate pairs, returns the equivalent HEX codepoint.
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```js
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twemoji.convert.toCodePoint('\ud83c\udde8\ud83c\uddf3');
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// "1f1e8-1f1f3"
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twemoji.convert.toCodePoint('\ud83c\udde8\ud83c\uddf3', '~');
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// "1f1e8~1f1f3"
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```
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## Tips
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#### Inline Styles
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If you'd like to size the emoji according to the surrounding text, you can add the following CSS to your stylesheet:
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```
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img.emoji {
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height: 1em;
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width: 1em;
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margin: 0 .05em 0 .1em;
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vertical-align: -0.1em;
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}
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```
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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.
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#### UTF-8 Character Set
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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>`
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```html
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<meta charset="utf-8">
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```
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#### Exclude Characters (V1)
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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:
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```js
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twemoji.parse(document.body, {
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callback: function(icon, options, variant) {
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switch ( icon ) {
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case 'a9': // © copyright
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case 'ae': // ® registered trademark
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case '2122': // ™ trademark
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return false;
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}
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return ''.concat(options.base, options.size, '/', icon, options.ext);
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}
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});
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```
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### Build
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If you'd like to test and/or contribute please follow these instructions.
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```bash
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# clone this repo
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git clone https://github.com/twitter/twemoji.git
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cd twemoji
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# install dependencies
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npm install
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# generate 2/twemoji*.js files
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./2/utils/generate
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```
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If you'd like to test and/or propose some changes to the V2 library please change the `./2/utils/generate` file at its end so that everything will be generated properly once launched.
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## Attribution Requirements
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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](https://wiki.creativecommons.org/Best_practices_for_attribution).
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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.
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## Community Projects
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* [Twemoji Awesome](http://ellekasai.github.io/twemoji-awesome/) by [@ellekasai](https://twitter.com/ellekasai/status/531979044036698112): Use Twemoji using CSS classes (like [Font Awesome](http://fortawesome.github.io/Font-Awesome/)).
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* [Twemoji Ruby](https://github.com/jollygoodcode/twemoji) by [@JollyGoodCode](https://twitter.com/jollygoodcode): Use Twemoji in Ruby.
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* [Twemoji for Pencil](https://github.com/nathanielw/Twemoji-for-Pencil) by [@Nathanielnw](https://twitter.com/nathanielnw): Use Twemoji in Pencil.
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* [FrwTwemoji - Twemoji in dotnet](http://github.frenchw.net/FrwTwemoji/) by [@FrenchW](https://twitter.com/frenchw): Use Twemoji in any dotnet project (C#, asp.net ...).
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* [Emojiawesome - Twemoji for Yellow](https://github.com/datenstrom/yellow-plugins/tree/master/emojiawesome) by [@datenstrom](https://github.com/datenstrom/): Use Twemoji in Yellow CMS.
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* [EmojiPanel for Twitter](https://github.com/danbovey/EmojiPanel) by [@danielbovey](https://twitter.com/danielbovey/status/749580050274582528): Insert Twemoji into your tweets on twitter.com.
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* [Twitter Color Emoji font](https://github.com/eosrei/twemoji-color-font) by [@bderickson](https://twitter.com/bderickson): Use Twemoji as your system default font on Linux & OS X.
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* [Emojica](https://github.com/xoudini/emojica) by [@xoudini](https://twitter.com/xoudini): An iOS framework allowing you to replace all standard emoji in strings with Twemoji.
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## Committers and Contributors
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* Tom Wuttke (Twitter)
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* Bryan Haggerty (Twitter)
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* Andrea Giammarchi (ex-Twitter)
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* Joen Asmussen (WordPress)
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* Marcus Kazmierczak (WordPress)
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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.
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The rules for contributing are available in the `CONTRIBUTING.md` file.
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Thank you to all of our [contributors](https://github.com/twitter/twemoji/graphs/contributors).
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## License
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Copyright 2016 Twitter, Inc and other contributors
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Code licensed under the MIT License: http://opensource.org/licenses/MIT
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Graphics licensed under CC-BY 4.0: https://creativecommons.org/licenses/by/4.0/
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