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					86 lines
				
				2.6 KiB
			
		
		
			
		
	
	
					86 lines
				
				2.6 KiB
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											4 years ago
										 
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								'use strict';
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								var GetIntrinsic = require('get-intrinsic');
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								var $RangeError = GetIntrinsic('%RangeError%');
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								var $TypeError = GetIntrinsic('%TypeError%');
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								var assign = require('object.assign');
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								var isPropertyDescriptor = require('../helpers/isPropertyDescriptor');
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								var IsArray = require('./IsArray');
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								var IsAccessorDescriptor = require('./IsAccessorDescriptor');
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								var IsDataDescriptor = require('./IsDataDescriptor');
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								var OrdinaryDefineOwnProperty = require('./OrdinaryDefineOwnProperty');
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								var OrdinaryGetOwnProperty = require('./OrdinaryGetOwnProperty');
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								var ToNumber = require('./ToNumber');
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								var ToString = require('./ToString');
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								var ToUint32 = require('./ToUint32');
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								var Type = require('./Type');
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								// https://ecma-international.org/ecma-262/6.0/#sec-arraysetlength
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								// eslint-disable-next-line max-statements, max-lines-per-function
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								module.exports = function ArraySetLength(A, Desc) {
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									if (!IsArray(A)) {
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										throw new $TypeError('Assertion failed: A must be an Array');
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									}
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									if (!isPropertyDescriptor({
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										Type: Type,
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										IsDataDescriptor: IsDataDescriptor,
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										IsAccessorDescriptor: IsAccessorDescriptor
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									}, Desc)) {
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										throw new $TypeError('Assertion failed: Desc must be a Property Descriptor');
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									}
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									if (!('[[Value]]' in Desc)) {
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										return OrdinaryDefineOwnProperty(A, 'length', Desc);
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									}
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									var newLenDesc = assign({}, Desc);
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									var newLen = ToUint32(Desc['[[Value]]']);
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									var numberLen = ToNumber(Desc['[[Value]]']);
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									if (newLen !== numberLen) {
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										throw new $RangeError('Invalid array length');
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									}
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									newLenDesc['[[Value]]'] = newLen;
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									var oldLenDesc = OrdinaryGetOwnProperty(A, 'length');
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									if (!IsDataDescriptor(oldLenDesc)) {
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										throw new $TypeError('Assertion failed: an array had a non-data descriptor on `length`');
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									}
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									var oldLen = oldLenDesc['[[Value]]'];
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									if (newLen >= oldLen) {
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										return OrdinaryDefineOwnProperty(A, 'length', newLenDesc);
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									}
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									if (!oldLenDesc['[[Writable]]']) {
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										return false;
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									}
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									var newWritable;
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									if (!('[[Writable]]' in newLenDesc) || newLenDesc['[[Writable]]']) {
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										newWritable = true;
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									} else {
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										newWritable = false;
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										newLenDesc['[[Writable]]'] = true;
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									}
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									var succeeded = OrdinaryDefineOwnProperty(A, 'length', newLenDesc);
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									if (!succeeded) {
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										return false;
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									}
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									while (newLen < oldLen) {
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										oldLen -= 1;
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										// eslint-disable-next-line no-param-reassign
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										var deleteSucceeded = delete A[ToString(oldLen)];
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										if (!deleteSucceeded) {
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											newLenDesc['[[Value]]'] = oldLen + 1;
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											if (!newWritable) {
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												newLenDesc['[[Writable]]'] = false;
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												OrdinaryDefineOwnProperty(A, 'length', newLenDesc);
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												return false;
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											}
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										}
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									}
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									if (!newWritable) {
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										return OrdinaryDefineOwnProperty(A, 'length', { '[[Writable]]': false });
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									}
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									return true;
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								};
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