1'use strict'; 2 3var toStr = Object.prototype.toString; 4 5var isPrimitive = require('./helpers/isPrimitive'); 6 7var isCallable = require('is-callable'); 8 9// http://ecma-international.org/ecma-262/5.1/#sec-8.12.8 10var ES5internalSlots = { 11 '[[DefaultValue]]': function (O) { 12 var actualHint; 13 if (arguments.length > 1) { 14 actualHint = arguments[1]; 15 } else { 16 actualHint = toStr.call(O) === '[object Date]' ? String : Number; 17 } 18 19 if (actualHint === String || actualHint === Number) { 20 var methods = actualHint === String ? ['toString', 'valueOf'] : ['valueOf', 'toString']; 21 var value, i; 22 for (i = 0; i < methods.length; ++i) { 23 if (isCallable(O[methods[i]])) { 24 value = O[methods[i]](); 25 if (isPrimitive(value)) { 26 return value; 27 } 28 } 29 } 30 throw new TypeError('No default value'); 31 } 32 throw new TypeError('invalid [[DefaultValue]] hint supplied'); 33 } 34}; 35 36// http://ecma-international.org/ecma-262/5.1/#sec-9.1 37module.exports = function ToPrimitive(input) { 38 if (isPrimitive(input)) { 39 return input; 40 } 41 if (arguments.length > 1) { 42 return ES5internalSlots['[[DefaultValue]]'](input, arguments[1]); 43 } 44 return ES5internalSlots['[[DefaultValue]]'](input); 45}; 46