# Twemoji Legacy API (V1)

## Usage

### CDN Support

The folks over at [MaxCDN](https://www.maxcdn.com) have graciously provided CDN support.

Use the following in the `<head>` tag of your HTML document(s):

```html
<script src="https://twemoji.maxcdn.com/1/twemoji.min.js" crossorigin="anonymous"></script>
```

This guarantees that you are using the V1 version of the library.

### 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](https://github.com/twitter/twemoji#string-parsing) and [DOM parsing](https://github.com/twitter/twemoji#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 `&lt;script&gt;` 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.

```js
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.

```js
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.

```js
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.

```js
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*.

```js
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.

```js
  {
    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:

```js
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:

```js
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.

```js
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.

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

### twemoji.convert.toCodePoint()

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

```js
 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:

```css
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>`

```html
<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:

```js
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.
