mirror of https://github.com/jkjoy/sunpeiwen.git
46 lines
1.2 KiB
JavaScript
46 lines
1.2 KiB
JavaScript
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'use strict';
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var toStr = Object.prototype.toString;
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var isPrimitive = require('./helpers/isPrimitive');
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var isCallable = require('is-callable');
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// http://ecma-international.org/ecma-262/5.1/#sec-8.12.8
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var ES5internalSlots = {
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'[[DefaultValue]]': function (O) {
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var actualHint;
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if (arguments.length > 1) {
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actualHint = arguments[1];
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} else {
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actualHint = toStr.call(O) === '[object Date]' ? String : Number;
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}
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if (actualHint === String || actualHint === Number) {
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var methods = actualHint === String ? ['toString', 'valueOf'] : ['valueOf', 'toString'];
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var value, i;
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for (i = 0; i < methods.length; ++i) {
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if (isCallable(O[methods[i]])) {
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value = O[methods[i]]();
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if (isPrimitive(value)) {
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return value;
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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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throw new TypeError('invalid [[DefaultValue]] hint supplied');
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}
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};
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// http://ecma-international.org/ecma-262/5.1/#sec-9.1
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module.exports = function ToPrimitive(input) {
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if (isPrimitive(input)) {
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return input;
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}
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if (arguments.length > 1) {
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return ES5internalSlots['[[DefaultValue]]'](input, arguments[1]);
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}
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return ES5internalSlots['[[DefaultValue]]'](input);
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};
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