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49 lines
2.1 KiB
49 lines
2.1 KiB
'use strict'; |
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var $ = require('../internals/export'); |
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var isObject = require('../internals/is-object'); |
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var isArray = require('../internals/is-array'); |
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var toAbsoluteIndex = require('../internals/to-absolute-index'); |
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var toLength = require('../internals/to-length'); |
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var toIndexedObject = require('../internals/to-indexed-object'); |
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var createProperty = require('../internals/create-property'); |
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var wellKnownSymbol = require('../internals/well-known-symbol'); |
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var arrayMethodHasSpeciesSupport = require('../internals/array-method-has-species-support'); |
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var arrayMethodUsesToLength = require('../internals/array-method-uses-to-length'); |
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var HAS_SPECIES_SUPPORT = arrayMethodHasSpeciesSupport('slice'); |
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var USES_TO_LENGTH = arrayMethodUsesToLength('slice', { ACCESSORS: true, 0: 0, 1: 2 }); |
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var SPECIES = wellKnownSymbol('species'); |
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var nativeSlice = [].slice; |
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var max = Math.max; |
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// `Array.prototype.slice` method |
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// https://tc39.github.io/ecma262/#sec-array.prototype.slice |
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// fallback for not array-like ES3 strings and DOM objects |
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$({ target: 'Array', proto: true, forced: !HAS_SPECIES_SUPPORT || !USES_TO_LENGTH }, { |
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slice: function slice(start, end) { |
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var O = toIndexedObject(this); |
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var length = toLength(O.length); |
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var k = toAbsoluteIndex(start, length); |
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var fin = toAbsoluteIndex(end === undefined ? length : end, length); |
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// inline `ArraySpeciesCreate` for usage native `Array#slice` where it's possible |
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var Constructor, result, n; |
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if (isArray(O)) { |
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Constructor = O.constructor; |
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// cross-realm fallback |
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if (typeof Constructor == 'function' && (Constructor === Array || isArray(Constructor.prototype))) { |
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Constructor = undefined; |
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} else if (isObject(Constructor)) { |
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Constructor = Constructor[SPECIES]; |
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if (Constructor === null) Constructor = undefined; |
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} |
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if (Constructor === Array || Constructor === undefined) { |
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return nativeSlice.call(O, k, fin); |
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} |
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} |
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result = new (Constructor === undefined ? Array : Constructor)(max(fin - k, 0)); |
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for (n = 0; k < fin; k++, n++) if (k in O) createProperty(result, n, O[k]); |
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result.length = n; |
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return result; |
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} |
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});
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