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node_modules/is-symbol/test/index.js 2.53 KB
aaac7fed   liuqimichale   add
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  'use strict';
  
  var test = require('tape');
  var isSymbol = require('../index');
  
  var forEach = function (arr, func) {
  	var i;
  	for (i = 0; i < arr.length; ++i) {
  		func(arr[i], i, arr);
  	}
  };
  
  var hasSymbols = require('has-symbols')();
  var inspect = require('object-inspect');
  var debug = function (v, m) { return inspect(v) + ' ' + m; };
  
  test('non-symbol values', function (t) {
  	var nonSymbols = [
  		true,
  		false,
  		Object(true),
  		Object(false),
  		null,
  		undefined,
  		{},
  		[],
  		/a/g,
  		'string',
  		42,
  		new Date(),
  		function () {},
  		NaN
  	];
  	t.plan(nonSymbols.length);
  	forEach(nonSymbols, function (nonSymbol) {
  		t.equal(false, isSymbol(nonSymbol), debug(nonSymbol, 'is not a symbol'));
  	});
  	t.end();
  });
  
  test('faked symbol values', function (t) {
  	t.test('real symbol valueOf', { skip: !hasSymbols }, function (st) {
  		var fakeSymbol = { valueOf: function () { return Symbol('foo'); } };
  		st.equal(false, isSymbol(fakeSymbol), 'object with valueOf returning a symbol is not a symbol');
  		st.end();
  	});
  
  	t.test('faked @@toStringTag', { skip: !hasSymbols || !Symbol.toStringTag }, function (st) {
  		var fakeSymbol = { valueOf: function () { return Symbol('foo'); } };
  		fakeSymbol[Symbol.toStringTag] = 'Symbol';
  		st.equal(false, isSymbol(fakeSymbol), 'object with fake Symbol @@toStringTag and valueOf returning a symbol is not a symbol');
  		var notSoFakeSymbol = { valueOf: function () { return 42; } };
  		notSoFakeSymbol[Symbol.toStringTag] = 'Symbol';
  		st.equal(false, isSymbol(notSoFakeSymbol), 'object with fake Symbol @@toStringTag and valueOf not returning a symbol is not a symbol');
  		st.end();
  	});
  
  	var fakeSymbolString = { toString: function () { return 'Symbol(foo)'; } };
  	t.equal(false, isSymbol(fakeSymbolString), 'object with toString returning Symbol(foo) is not a symbol');
  
  	t.end();
  });
  
  test('Symbol support', { skip: !hasSymbols }, function (t) {
  	t.test('well-known Symbols', function (st) {
  		var isWellKnown = function filterer(name) {
  			return name !== 'for' && name !== 'keyFor' && !(name in filterer);
  		};
  		var wellKnownSymbols = Object.getOwnPropertyNames(Symbol).filter(isWellKnown);
  		wellKnownSymbols.forEach(function (name) {
  			var sym = Symbol[name];
  			st.equal(true, isSymbol(sym), debug(sym, ' is a symbol'));
  		});
  		st.end();
  	});
  
  	t.test('user-created symbols', function (st) {
  		var symbols = [
  			Symbol(),
  			Symbol('foo'),
  			Symbol['for']('foo'),
  			Object(Symbol('object'))
  		];
  		symbols.forEach(function (sym) {
  			st.equal(true, isSymbol(sym), debug(sym, ' is a symbol'));
  		});
  		st.end();
  	});
  
  	t.end();
  });