Emoji-patterns NPM

Emoji Patterns

Description

This Node module returns a JSON-compatible object literal containing both basic and compound emoji pattern strings.

Available Patterns

The following patterns are generated using the information parsed from the Emoji 14.0 data files emoji-data.txt, emoji-sequences.txt and emoji-zwj-sequences.txt:

Basic_Emoji
Emoji
Emoji_Component
Emoji_Keycap_Sequence
Emoji_Modifier
Emoji_Modifier_Base
Emoji_Presentation
Extended_Pictographic
RGI_Emoji_Flag_Sequence
RGI_Emoji_Modifier_Sequence
RGI_Emoji_Tag_Sequence
RGI_Emoji_ZWJ_Sequence

These basic patterns are then used to generate two more complex compound patterns:

Emoji_All
Emoji_Keyboard

const
{
    Basic_Emoji,
    Emoji,
    Emoji_Component,
    Emoji_Keycap_Sequence,
    Emoji_Modifier,
    Emoji_Modifier_Base,
    Emoji_Presentation,
    Extended_Pictographic,
    RGI_Emoji_Flag_Sequence,
    RGI_Emoji_Modifier_Sequence,
    RGI_Emoji_Tag_Sequence,
    RGI_Emoji_ZWJ_Sequence
} = emojiPatterns;

// Keyboard emoji only (fully-qualified and components)
emojiPatterns["Emoji_Keyboard"] = `(?:${RGI_Emoji_ZWJ_Sequence}|${Emoji_Keycap_Sequence}|${RGI_Emoji_Flag_Sequence}|${RGI_Emoji_Tag_Sequence}|${Emoji_Modifier_Base}${Emoji_Modifier}|${Emoji_Presentation}|${Emoji}\\uFE0F)`;
// All emoji (U+FE0F optional)
emojiPatterns["Emoji_All"] = emojiPatterns["Emoji_Keyboard"].replace (/(\\u{FE0F}|\\uFE0F)/gi, '$1?');

Notes

The order of the basic patterns in the compound patterns is critical. Since a regular expression engine is eager and stops searching as soon as it finds a valid match (i.e., it always returns the leftmost match), the longest patterns must come first. The same strategy is also used when generating the RGI_Emoji_ZWJ_Sequence pattern itself.
In the compound patterns, ${Emoji_Modifier_Base}${Emoji_Modifier} can be replaced by ${RGI_Emoji_Modifier_Sequence} which is strictly equivalent (but more verbose).
Likewise, ${Emoji_Presentation}|${Emoji}\\uFE0F could be replaced by ${Basic_Emoji} (which should actually be called ${Basic_Emoji_Sequence} for the sake of consistency), but the latter is more restrictive since it only contains the 5 skin tone and 4 hairstyle components, excluding the 12 keycap bases and the 26 singleton regional indicators.
Providing patterns as strings instead of regular expressions does require the extra step of using new RegExp () to actually make use of them, but it has two main advantages:
- Flags can be set differently depending on how the patterns are used.
- The patterns can be further modified before being turned into regular expressions; for instance, unwanted sub-patterns can be discarded by replacing them with an empty string, or the pattern can be embedded into a larger one. See examples below.

Installing

Switch to your project directory (cd) then run:

npm install emoji-patterns

Testing

A basic test can be performed by running the following command line from the package directory:

npm test

Examples

Testing whether an emoji has a keyboard status or not

const emojiPatterns = require ('emoji-patterns');
const emojiKeyboardRegex = new RegExp ('^' + emojiPatterns["Emoji_Keyboard"] + '$', 'u');
console.log (emojiKeyboardRegex.test ("❤️"));
// -> true
console.log (emojiKeyboardRegex.test ("❤"));
// -> false

Extracting all emoji from a string

const emojiPatterns = require ('emoji-patterns');
const emojiAllRegex = new RegExp (emojiPatterns["Emoji_All"], 'gu');
console.log (JSON.stringify ("AaĀā#*0❤🇦愛爱❤️애💜".match (emojiAllRegex)));
// -> ["#","*","0","❤","🇦","❤️","💜"]

Extracting all emoji from a string, except keycap bases and singleton regional indicators

const emojiPatterns = require ('emoji-patterns');
const emojiAllPattern = emojiPatterns["Emoji_All"];
const customPattern = emojiAllPattern.replace (/\\u0023\\u002A\\u0030-\\u0039|\\u\{1F1E6\}-\\u\{1F1FF\}/gi, '');
const customRegex = new RegExp (customPattern, 'gu');
console.log (JSON.stringify ("AaĀā#*0❤🇦愛爱❤️애💜".match (customRegex)));
// -> ["❤","❤️","💜"]

Extracting all keyboard-status emoji from a string

const emojiPatterns = require ('emoji-patterns');
const emojiAllRegex = new RegExp (emojiPatterns["Emoji_All"], 'gu');
const emojiKeyboardRegex = new RegExp ('^' + emojiPatterns["Emoji_Keyboard"] + '$', 'u');
let emojiList = "AaĀā#*0❤🇦愛爱❤️애💜".match (emojiAllRegex);
if (emojiList)
{
    emojiList = emojiList.filter (emoji => emojiKeyboardRegex.test (emoji));
}
console.log (JSON.stringify (emojiList));
// -> ["🇦","❤️","💜"]

Removing all emoji from a string

const emojiPatterns = require ('emoji-patterns');
const emojiAllRegex = new RegExp (emojiPatterns["Emoji_All"], 'gu');
console.log (JSON.stringify ("AaĀā#*0❤🇦愛爱❤️애💜".replace (emojiAllRegex, "")));
// -> "AaĀā愛爱애"

Caveats

The basic patterns strictly follow the information extracted from the data files. Therefore, the following characters are considered Emoji in the emoji-data.txt file, although they are omitted in the emoji-test.txt file, as well as in the CLDR annotation files provided in XML format:
- 12 keycap bases: number sign '#', asterisk '*', digits '0' to '9'
- 26 singleton regional indicators: '🇦' to '🇿'
The regular expressions must include a 'u' flag, since the patterns make use of the new type of Unicode escape sequences: \u{1F4A9}.
The two main regular expression patterns Emoji_All and Emoji_Keyboard are pretty big, around 65KB each...