Unfloyded/Legamunt
0
0
Fork 0
Code Activity

Faster emojify() by avoiding str.replace() entirely (#4049)

Browse source
This commit is contained in:
Nolan Lawson 2017-07-03 02:02:36 -07:00 • committed by Eugen Rochko
parent 331f0953e9
commit e282580101
4 changed files with 71 additions and 37 deletions
Download patch file Download diff file Expand all files Collapse all files

69
app/javascript/mastodon/emoji.js
View file

@ -1,60 +1,55 @@
import emojione from 'emojione';
import Trie from 'substring-trie';
const toImage = str => shortnameToImage(unicodeToImage(str));
const mappedUnicode = emojione.mapUnicodeToShort();
const trie = new Trie(Object.keys(emojione.jsEscapeMap));
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/${filename}.svg" />`;
});
};
const shortnameToImage = str => {
// This walks through the string from end to start, ignoring any tags (<p>, <br>, etc.)
// and replacing valid shortnames like :smile: and :wink: that _aren't_ within
// tags with an <img> version.
// The goal is to be the same as an emojione.regShortNames replacement, but faster.
// The reason we go backwards is because then we can replace substrings as we go.
let i = str.length;
function emojify(str) {
// This walks through the string from start to end, ignoring any tags (<p>, <br>, etc.)
// and replacing valid shortnames like :smile: and :wink: as well as unicode strings
// that _aren't_ within tags with an <img> version.
// The goal is to be the same as an emojione.regShortNames/regUnicode replacement, but faster.
let i = -1;
let insideTag = false;
let insideShortname = false;
let shortnameEndIndex = -1;
while (i--) {
let shortnameStartIndex = -1;
let match;
while (++i < str.length) {
const char = str.charAt(i);
if (insideShortname && char === ':') {
const shortname = str.substring(i, shortnameEndIndex + 1);
const shortname = str.substring(shortnameStartIndex, i + 1);
if (shortname in emojione.emojioneList) {
const unicode = emojione.emojioneList[shortname].unicode[emojione.emojioneList[shortname].unicode.length - 1];
const alt = emojione.convert(unicode.toUpperCase());
const replacement = `<img draggable="false" class="emojione" alt="${alt}" title="${shortname}" src="/emoji/${unicode}.svg" />`;
str = str.substring(0, i) + replacement + str.substring(shortnameEndIndex + 1);
str = str.substring(0, shortnameStartIndex) + replacement + str.substring(i + 1);
i += (replacement.length - shortname.length - 1); // jump ahead the length we've added to the string
} else {
i++; // stray colon, try again
i--; // stray colon, try again
}
insideShortname = false;
} else if (insideTag && char === '<') {
} else if (insideTag && char === '>') {
insideTag = false;
} else if (char === '>') {
} else if (char === '<') {
insideTag = true;
insideShortname = false;
} else if (!insideTag && char === ':') {
insideShortname = true;
shortnameEndIndex = i;
shortnameStartIndex = i;
} else if (!insideTag && (match = trie.search(str.substring(i)))) {
const unicodeStr = match;
if (unicodeStr in emojione.jsEscapeMap) {
const unicode = emojione.jsEscapeMap[unicodeStr];
const short = mappedUnicode[unicode];
const filename = emojione.emojioneList[short].fname;
const alt = emojione.convert(unicode.toUpperCase());
const replacement = `<img draggable="false" class="emojione" alt="${alt}" title="${short}" src="/emoji/${filename}.svg" />`;
str = str.substring(0, i) + replacement + str.substring(i + unicodeStr.length);
i += (replacement.length - unicodeStr.length); // jump ahead the length we've added to the string
}
}
}
return str;
};
}
export default function emojify(text) {
return toImage(text);
};
export default emojify;