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							85 lines
						
					
					
						
							2.6 KiB
						
					
					
				
			
		
		
	
	
							85 lines
						
					
					
						
							2.6 KiB
						
					
					
				'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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