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74 lines
2.1 KiB
74 lines
2.1 KiB
'use strict'; |
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var hasSymbols = typeof Symbol === 'function' && typeof Symbol.iterator === 'symbol'; |
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var isPrimitive = require('./helpers/isPrimitive'); |
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var isCallable = require('is-callable'); |
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var isDate = require('is-date-object'); |
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var isSymbol = require('is-symbol'); |
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var ordinaryToPrimitive = function OrdinaryToPrimitive(O, hint) { |
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if (typeof O === 'undefined' || O === null) { |
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throw new TypeError('Cannot call method on ' + O); |
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} |
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if (typeof hint !== 'string' || (hint !== 'number' && hint !== 'string')) { |
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throw new TypeError('hint must be "string" or "number"'); |
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} |
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var methodNames = hint === 'string' ? ['toString', 'valueOf'] : ['valueOf', 'toString']; |
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var method, result, i; |
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for (i = 0; i < methodNames.length; ++i) { |
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method = O[methodNames[i]]; |
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if (isCallable(method)) { |
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result = method.call(O); |
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if (isPrimitive(result)) { |
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return result; |
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} |
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} |
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} |
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throw new TypeError('No default value'); |
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}; |
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var GetMethod = function GetMethod(O, P) { |
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var func = O[P]; |
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if (func !== null && typeof func !== 'undefined') { |
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if (!isCallable(func)) { |
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throw new TypeError(func + ' returned for property ' + P + ' of object ' + O + ' is not a function'); |
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} |
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return func; |
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} |
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}; |
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// http://www.ecma-international.org/ecma-262/6.0/#sec-toprimitive |
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module.exports = function ToPrimitive(input, PreferredType) { |
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if (isPrimitive(input)) { |
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return input; |
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} |
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var hint = 'default'; |
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if (arguments.length > 1) { |
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if (PreferredType === String) { |
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hint = 'string'; |
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} else if (PreferredType === Number) { |
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hint = 'number'; |
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} |
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} |
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var exoticToPrim; |
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if (hasSymbols) { |
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if (Symbol.toPrimitive) { |
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exoticToPrim = GetMethod(input, Symbol.toPrimitive); |
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} else if (isSymbol(input)) { |
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exoticToPrim = Symbol.prototype.valueOf; |
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} |
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} |
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if (typeof exoticToPrim !== 'undefined') { |
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var result = exoticToPrim.call(input, hint); |
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if (isPrimitive(result)) { |
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return result; |
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} |
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throw new TypeError('unable to convert exotic object to primitive'); |
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} |
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if (hint === 'default' && (isDate(input) || isSymbol(input))) { |
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hint = 'string'; |
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} |
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return ordinaryToPrimitive(input, hint === 'default' ? 'number' : hint); |
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};
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