98 lines
2.2 KiB
JavaScript
98 lines
2.2 KiB
JavaScript
module.exports = {
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/**
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* Transform the values of an object via a mapper function
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* @param {Object} obj
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* @param {Function} mapper
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*/
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mapObject(obj, mapper) {
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const mappedObj = {};
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Object.keys(obj).forEach(key => { mappedObj[key] = mapper(key, obj[key]); });
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return mappedObj;
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},
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/**
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* Parses the attributes from a string taken from an HTML element start tag
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* E.g. ` a="one" b="two" `
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* @param {string} str
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*/
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parseAttributes(str) {
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const attrMap = {};
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let index = 0;
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skipSpace();
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while(index < str.length) {
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takeAttribute();
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skipSpace();
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}
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function takeAttribute() {
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const key = takeKey();
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skipSpace();
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if (tryEquals()) {
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skipSpace();
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const quote = tryQuote();
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attrMap[key] = takeValue(quote);
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// skip the closing quote or whitespace
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index++;
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} else {
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attrMap[key] = true;
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}
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}
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function skipSpace() {
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while(index < str.length && /\s/.test(str[index])) {
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index++;
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}
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}
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function tryEquals() {
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if (str[index] === '=') {
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index++;
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return true;
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}
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}
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function takeKey() {
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let startIndex = index;
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while(index < str.length && /[^\s=]/.test(str[index])) {
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index++;
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}
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return str.substring(startIndex, index);
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}
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function tryQuote() {
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const quote = str[index];
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if (['"', '\''].indexOf(quote) !== -1) {
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index++;
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return quote;
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}
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}
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function takeValue(quote) {
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let startIndex = index;
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if (quote) {
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while(index < str.length && str[index] !== quote) {
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index++;
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}
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if (index >= str.length) {
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throw new Error(`Unterminated quoted attribute value in \`${str}\`. Starting at ${startIndex}. Expected a ${quote} but got "end of string".`);
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}
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} else {
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while(index < str.length && /\S/.test(str[index])) {
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index++;
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}
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}
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return str.substring(startIndex, index);
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}
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return attrMap;
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},
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renderAttributes(attrMap) {
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return Object.keys(attrMap).map(key => (attrMap[key] === true) ? ` ${key}` : ` ${key}="${attrMap[key].replace(/"/g, '"')}"`).join('');
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}
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};
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