mirror of https://github.com/jkjoy/sunpeiwen.git
19 lines
762 B
JavaScript
19 lines
762 B
JavaScript
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// 21.1.3.18 String.prototype.startsWith(searchString [, position ])
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'use strict';
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var $export = require('./_export');
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var toLength = require('./_to-length');
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var context = require('./_string-context');
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var STARTS_WITH = 'startsWith';
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var $startsWith = ''[STARTS_WITH];
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$export($export.P + $export.F * require('./_fails-is-regexp')(STARTS_WITH), 'String', {
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startsWith: function startsWith(searchString /* , position = 0 */) {
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var that = context(this, searchString, STARTS_WITH);
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var index = toLength(Math.min(arguments.length > 1 ? arguments[1] : undefined, that.length));
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var search = String(searchString);
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return $startsWith
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? $startsWith.call(that, search, index)
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: that.slice(index, index + search.length) === search;
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}
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});
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