30 lines
660 B
JavaScript
30 lines
660 B
JavaScript
'use strict';
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const isRegexp = require('is-regexp');
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const flagMap = {
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global: 'g',
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ignoreCase: 'i',
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multiline: 'm',
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dotAll: 's',
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sticky: 'y',
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unicode: 'u'
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};
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module.exports = (regexp, options = {}) => {
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if (!isRegexp(regexp)) {
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throw new TypeError('Expected a RegExp instance');
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}
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const flags = Object.keys(flagMap).map(flag => (
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(typeof options[flag] === 'boolean' ? options[flag] : regexp[flag]) ? flagMap[flag] : ''
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)).join('');
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const clonedRegexp = new RegExp(options.source || regexp.source, flags);
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clonedRegexp.lastIndex = typeof options.lastIndex === 'number' ?
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options.lastIndex :
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regexp.lastIndex;
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return clonedRegexp;
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};
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