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87 lines
2.9 KiB
JavaScript
87 lines
2.9 KiB
JavaScript
/**
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* lodash 4.1.1 (Custom Build) <https://lodash.com/>
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* Build: `lodash modularize exports="npm" -o ./`
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* Copyright 2012-2016 The Dojo Foundation <http://dojofoundation.org/>
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* Based on Underscore.js 1.8.3 <http://underscorejs.org/LICENSE>
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* Copyright 2009-2016 Jeremy Ashkenas, DocumentCloud and Investigative Reporters & Editors
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* Available under MIT license <https://lodash.com/license>
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*/
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var charsStartIndex = require('lodash._charsstartindex'),
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toString = require('lodash.tostring');
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/** Used to match leading and trailing whitespace. */
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var reTrimStart = /^\s+/;
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/** Used to compose unicode character classes. */
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var rsAstralRange = '\\ud800-\\udfff',
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rsComboMarksRange = '\\u0300-\\u036f\\ufe20-\\ufe23',
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rsComboSymbolsRange = '\\u20d0-\\u20f0',
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rsVarRange = '\\ufe0e\\ufe0f';
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/** Used to compose unicode capture groups. */
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var rsAstral = '[' + rsAstralRange + ']',
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rsCombo = '[' + rsComboMarksRange + rsComboSymbolsRange + ']',
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rsFitz = '\\ud83c[\\udffb-\\udfff]',
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rsModifier = '(?:' + rsCombo + '|' + rsFitz + ')',
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rsNonAstral = '[^' + rsAstralRange + ']',
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rsRegional = '(?:\\ud83c[\\udde6-\\uddff]){2}',
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rsSurrPair = '[\\ud800-\\udbff][\\udc00-\\udfff]',
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rsZWJ = '\\u200d';
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/** Used to compose unicode regexes. */
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var reOptMod = rsModifier + '?',
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rsOptVar = '[' + rsVarRange + ']?',
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rsOptJoin = '(?:' + rsZWJ + '(?:' + [rsNonAstral, rsRegional, rsSurrPair].join('|') + ')' + rsOptVar + reOptMod + ')*',
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rsSeq = rsOptVar + reOptMod + rsOptJoin,
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rsSymbol = '(?:' + [rsNonAstral + rsCombo + '?', rsCombo, rsRegional, rsSurrPair, rsAstral].join('|') + ')';
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/** Used to match [string symbols](https://mathiasbynens.be/notes/javascript-unicode). */
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var reComplexSymbol = RegExp(rsFitz + '(?=' + rsFitz + ')|' + rsSymbol + rsSeq, 'g');
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/**
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* Converts `string` to an array.
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*
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* @private
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* @param {string} string The string to convert.
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* @returns {Array} Returns the converted array.
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*/
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function stringToArray(string) {
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return string.match(reComplexSymbol);
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}
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/**
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* Removes leading whitespace or specified characters from `string`.
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*
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* @static
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* @memberOf _
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* @category String
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* @param {string} [string=''] The string to trim.
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* @param {string} [chars=whitespace] The characters to trim.
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* @param- {Object} [guard] Enables use as an iteratee for functions like `_.map`.
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* @returns {string} Returns the trimmed string.
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* @example
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*
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* _.trimStart(' abc ');
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* // => 'abc '
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*
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* _.trimStart('-_-abc-_-', '_-');
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* // => 'abc-_-'
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*/
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function trimStart(string, chars, guard) {
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string = toString(string);
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if (!string) {
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return string;
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}
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if (guard || chars === undefined) {
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return string.replace(reTrimStart, '');
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}
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chars = (chars + '');
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if (!chars) {
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return string;
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}
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var strSymbols = stringToArray(string);
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return strSymbols.slice(charsStartIndex(strSymbols, stringToArray(chars))).join('');
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}
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module.exports = trimStart;
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