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53 lines
1.6 KiB
53 lines
1.6 KiB
'use strict'; |
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var GetIntrinsic = require('get-intrinsic'); |
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var $ArrayPrototype = GetIntrinsic('%Array.prototype%'); |
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var $RangeError = GetIntrinsic('%RangeError%'); |
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var $SyntaxError = GetIntrinsic('%SyntaxError%'); |
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var $TypeError = GetIntrinsic('%TypeError%'); |
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var IsInteger = require('./IsInteger'); |
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var MAX_ARRAY_LENGTH = Math.pow(2, 32) - 1; |
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var $setProto = GetIntrinsic('%Object.setPrototypeOf%', true) || ( |
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// eslint-disable-next-line no-proto, no-negated-condition |
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[].__proto__ !== $ArrayPrototype |
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? null |
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: function (O, proto) { |
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O.__proto__ = proto; // eslint-disable-line no-proto, no-param-reassign |
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return O; |
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} |
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); |
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// https://ecma-international.org/ecma-262/6.0/#sec-arraycreate |
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module.exports = function ArrayCreate(length) { |
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if (!IsInteger(length) || length < 0) { |
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throw new $TypeError('Assertion failed: `length` must be an integer Number >= 0'); |
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} |
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if (length > MAX_ARRAY_LENGTH) { |
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throw new $RangeError('length is greater than (2**32 - 1)'); |
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} |
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var proto = arguments.length > 1 ? arguments[1] : $ArrayPrototype; |
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var A = []; // steps 5 - 7, and 9 |
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if (proto !== $ArrayPrototype) { // step 8 |
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if (!$setProto) { |
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throw new $SyntaxError('ArrayCreate: a `proto` argument that is not `Array.prototype` is not supported in an environment that does not support setting the [[Prototype]]'); |
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} |
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$setProto(A, proto); |
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} |
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if (length !== 0) { // bypasses the need for step 2 |
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A.length = length; |
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} |
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/* step 10, the above as a shortcut for the below |
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OrdinaryDefineOwnProperty(A, 'length', { |
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'[[Configurable]]': false, |
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'[[Enumerable]]': false, |
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'[[Value]]': length, |
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'[[Writable]]': true |
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}); |
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*/ |
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return A; |
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};
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