Faster emojify() by avoiding str.replace() entirely (#4049)
Nolan Lawson
7 years ago
committed by
Eugen Rochko
parent
48e8f704c8
commit
28da1d54d5
@ -1,60 +1,55 @@
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import emojione from 'emojione';
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import Trie from 'substring-trie';
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const toImage = str => shortnameToImage(unicodeToImage(str));
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const unicodeToImage = str => {
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const mappedUnicode = emojione.mapUnicodeToShort();
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const trie = new Trie(Object.keys(emojione.jsEscapeMap));
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return str.replace(emojione.regUnicode, unicodeChar => {
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if (typeof unicodeChar === 'undefined' || unicodeChar === '' || !(unicodeChar in emojione.jsEscapeMap)) {
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return unicodeChar;
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}
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const unicode = emojione.jsEscapeMap[unicodeChar];
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const short = mappedUnicode[unicode];
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const filename = emojione.emojioneList[short].fname;
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const alt = emojione.convert(unicode.toUpperCase());
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return `<img draggable="false" class="emojione" alt="${alt}" title="${short}" src="/emoji/${filename}.svg" />`;
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});
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};
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const shortnameToImage = str => {
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// This walks through the string from end to start, ignoring any tags (<p>, <br>, etc.)
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// and replacing valid shortnames like :smile: and :wink: that _aren't_ within
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// tags with an <img> version.
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// The goal is to be the same as an emojione.regShortNames replacement, but faster.
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// The reason we go backwards is because then we can replace substrings as we go.
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let i = str.length;
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function emojify(str) {
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// This walks through the string from start to end, ignoring any tags (<p>, <br>, etc.)
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// and replacing valid shortnames like :smile: and :wink: as well as unicode strings
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// that _aren't_ within tags with an <img> version.
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// The goal is to be the same as an emojione.regShortNames/regUnicode replacement, but faster.
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let i = -1;
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let insideTag = false;
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let insideShortname = false;
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let shortnameEndIndex = -1;
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while (i--) {
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let shortnameStartIndex = -1;
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let match;
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while (++i < str.length) {
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const char = str.charAt(i);
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if (insideShortname && char === ':') {
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const shortname = str.substring(i, shortnameEndIndex + 1);
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const shortname = str.substring(shortnameStartIndex, i + 1);
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if (shortname in emojione.emojioneList) {
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const unicode = emojione.emojioneList[shortname].unicode[emojione.emojioneList[shortname].unicode.length - 1];
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const alt = emojione.convert(unicode.toUpperCase());
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const replacement = `<img draggable="false" class="emojione" alt="${alt}" title="${shortname}" src="/emoji/${unicode}.svg" />`;
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str = str.substring(0, i) + replacement + str.substring(shortnameEndIndex + 1);
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str = str.substring(0, shortnameStartIndex) + replacement + str.substring(i + 1);
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i += (replacement.length - shortname.length - 1); // jump ahead the length we've added to the string
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} else {
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i++; // stray colon, try again
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i--; // stray colon, try again
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}
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insideShortname = false;
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} else if (insideTag && char === '<') {
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} else if (insideTag && char === '>') {
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insideTag = false;
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} else if (char === '>') {
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} else if (char === '<') {
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insideTag = true;
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insideShortname = false;
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} else if (!insideTag && char === ':') {
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insideShortname = true;
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shortnameEndIndex = i;
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shortnameStartIndex = i;
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} else if (!insideTag && (match = trie.search(str.substring(i)))) {
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const unicodeStr = match;
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if (unicodeStr in emojione.jsEscapeMap) {
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const unicode = emojione.jsEscapeMap[unicodeStr];
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const short = mappedUnicode[unicode];
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const filename = emojione.emojioneList[short].fname;
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const alt = emojione.convert(unicode.toUpperCase());
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const replacement = `<img draggable="false" class="emojione" alt="${alt}" title="${short}" src="/emoji/${filename}.svg" />`;
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str = str.substring(0, i) + replacement + str.substring(i + unicodeStr.length);
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i += (replacement.length - unicodeStr.length); // jump ahead the length we've added to the string
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}
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}
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}
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return str;
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};
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}
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export default function emojify(text) {
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return toImage(text);
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};
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export default emojify;
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