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							52 lines
						
					
					
						
							1.3 KiB
						
					
					
				
			
		
		
	
	
							52 lines
						
					
					
						
							1.3 KiB
						
					
					
				'use strict'; | 
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var GetIntrinsic = require('get-intrinsic'); | 
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var callBound = require('call-bind/callBound'); | 
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var $TypeError = GetIntrinsic('%TypeError%'); | 
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var $charAt = callBound('String.prototype.charAt'); | 
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var isString = require('is-string'); | 
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var isNegativeZero = require('is-negative-zero'); | 
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var unbox = require('unbox-primitive'); | 
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var CanonicalNumericIndexString = require('./CanonicalNumericIndexString'); | 
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var IsInteger = require('./IsInteger'); | 
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var IsPropertyKey = require('./IsPropertyKey'); | 
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var Type = require('./Type'); | 
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// https://262.ecma-international.org/6.0/#sec-stringgetindexproperty | 
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module.exports = function StringGetIndexProperty(S, P) { | 
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	if (typeof S === 'string' || !isString(S)) { | 
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		throw new $TypeError('Assertion failed: `S` must be a boxed String Object'); | 
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	} | 
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	if (!IsPropertyKey(P)) { | 
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		throw new $TypeError('Assertion failed: `P` must be a Property Key'); | 
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	} | 
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	if (Type(P) !== 'String') { | 
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		return void undefined; | 
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	} | 
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	var index = CanonicalNumericIndexString(P); | 
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	if (typeof index === 'undefined' || !IsInteger(index) || isNegativeZero(index)) { | 
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		return void undefined; | 
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	} | 
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	var str = unbox(S); | 
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	var len = str.length; | 
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	if (index < 0 || len <= index) { | 
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		return void undefined; | 
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	} | 
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	var resultStr = $charAt(str, index); | 
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	return { | 
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		'[[Configurable]]': false, | 
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		'[[Enumerable]]': true, | 
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		'[[Value]]': resultStr, | 
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		'[[Writable]]': false | 
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	}; | 
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};
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