Testing the behavior of Object.is

gistfile1.js

// Test my hypothesis that Object.is(a, b) is the same as a === b.
// Log an error if they're different.
var numTests = 0;
function test(a, b) {
	if ((Object.is(a, b)) !== (a === b)) {
		console.error('Object.is is different from === for ' + a + ' and ' + b);
	}
	numTests ++;
}

// Basic number tests
for (var i = -100; i <= 100; i += .1) {
	for (var j = -100; j <= 100; j += .1) {
		test(i, j);
	}
}

// A function to generate random strings
function randomString() {
	var result = '';
	var i = Math.floor(Math.random() * 100);
	while (i --) {
		var charCode = Math.floor(Math.random() * 255);
		result += String.fromCharCode(charCode);
	}
	return result;
}

// Test the same string
for (var i = 0; i < 1000; i ++) {
	var s = randomString();
	test(s, s);
}

// Test different strings
for (var i = 0; i < 1000; i ++) {
	var a = randomString();
	var b = randomString();
	test(a, b);
}

// Test different String objects
for (var i = 0; i < 1000; i ++) {
	var a = new String(randomString());
	var b = new String(randomString());
	test(a, b);
}

// Test booleans
test(true, true);
test(true, false);
test(false, true);
test(false, false);
test(new Boolean(true), new Boolean(true));
test(new Boolean(true), new Boolean(false));
test(new Boolean(false), new Boolean(true));
test(new Boolean(false), new Boolean(false));

// Test objects
test({}, {});
test({ color: 'red' }, { color: 'red' });
test({ color: 'red' }, { color: 'orange' });
test({ tall: true }, { tall: false });
test({ tall: true }, { tall: true });

// Test arrays
test([], []);
test([5], [5]);
test([5], [12]);

// Test them weird types
var und = void 0;
var nan = 0 / 0;
var inf = 1 / 0;
test(und, und);
test(und, null);
test(und, nan);
test(und, inf);
test(null, und);
test(null, null);
test(null, nan);
test(null, inf);
test(nan, und);
test(nan, null);
test(nan, nan);
test(nan, inf);
test(inf, und);
test(inf, null);
test(inf, nan);
test(inf, inf);

// Test only one input
test();
for (var i = -100; i <= 100; i += .1)
	test(i);
test(true);
test(false);
test({});
test([]);
test(und);
test(null);
test(nan);
test(inf);

// All done!
console.log('Ran ' + numTests + ' tests.');

/*

See more about Object.is at this blog post:
<http://evanhahn.com/?p=1353>

by Evan Hahn (evanhahn.com)

************

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of this software dedicate any and all copyright interest in the
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successors. We intend this dedication to be an overt act of
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR
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ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
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For more information, please refer to <http://unlicense.org/>

*/