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23 lines
964 B
JavaScript
23 lines
964 B
JavaScript
6 years ago
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'use strict';
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var $export = require('./_export');
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var toIObject = require('./_to-iobject');
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var toInteger = require('./_to-integer');
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var toLength = require('./_to-length');
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var $native = [].lastIndexOf;
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var NEGATIVE_ZERO = !!$native && 1 / [1].lastIndexOf(1, -0) < 0;
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$export($export.P + $export.F * (NEGATIVE_ZERO || !require('./_strict-method')($native)), 'Array', {
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// 22.1.3.14 / 15.4.4.15 Array.prototype.lastIndexOf(searchElement [, fromIndex])
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lastIndexOf: function lastIndexOf(searchElement /* , fromIndex = @[*-1] */) {
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// convert -0 to +0
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if (NEGATIVE_ZERO) return $native.apply(this, arguments) || 0;
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var O = toIObject(this);
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var length = toLength(O.length);
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var index = length - 1;
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if (arguments.length > 1) index = Math.min(index, toInteger(arguments[1]));
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if (index < 0) index = length + index;
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for (;index >= 0; index--) if (index in O) if (O[index] === searchElement) return index || 0;
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return -1;
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}
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});
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