hometown/app/javascript/mastodon/emoji.js
Nolan Lawson a978b88997 Faster emojify() algorithm, avoid regex replace (#4019)
* Faster emojify() algorithm, avoid regex replace

* add semicolon
2017-06-30 17:29:22 +02:00

61 lines
2.3 KiB
JavaScript

import emojione from 'emojione';
const toImage = str => shortnameToImage(unicodeToImage(str));
const unicodeToImage = str => {
const mappedUnicode = emojione.mapUnicodeToShort();
return str.replace(emojione.regUnicode, unicodeChar => {
if (typeof unicodeChar === 'undefined' || unicodeChar === '' || !(unicodeChar in emojione.jsEscapeMap)) {
return unicodeChar;
}
const unicode = emojione.jsEscapeMap[unicodeChar];
const short = mappedUnicode[unicode];
const filename = emojione.emojioneList[short].fname;
const alt = emojione.convert(unicode.toUpperCase());
return `<img draggable="false" class="emojione" alt="${alt}" title="${short}" src="/emoji/${filename}.svg" />`;
});
};
const shortnameToImage = str => {
// This walks through the string from end to start, ignoring any tags (<p>, <br>, etc.)
// and replacing valid shortnames like :smile: and :wink: that _aren't_ within
// tags with an <img> version.
// The goal is to be the same as an emojione.regShortNames replacement, but faster.
// The reason we go backwards is because then we can replace substrings as we go.
let i = str.length;
let insideTag = false;
let insideShortname = false;
let shortnameEndIndex = -1;
while (i--) {
const char = str.charAt(i);
if (insideShortname && char === ':') {
const shortname = str.substring(i, shortnameEndIndex + 1);
if (shortname in emojione.emojioneList) {
const unicode = emojione.emojioneList[shortname].unicode[emojione.emojioneList[shortname].unicode.length - 1];
const alt = emojione.convert(unicode.toUpperCase());
const replacement = `<img draggable="false" class="emojione" alt="${alt}" title="${shortname}" src="/emoji/${unicode}.svg" />`;
str = str.substring(0, i) + replacement + str.substring(shortnameEndIndex + 1);
} else {
i++; // stray colon, try again
}
insideShortname = false;
} else if (insideTag && char === '<') {
insideTag = false;
} else if (char === '>') {
insideTag = true;
insideShortname = false;
} else if (!insideTag && char === ':') {
insideShortname = true;
shortnameEndIndex = i;
}
}
return str;
};
export default function emojify(text) {
return toImage(text);
};