es6.js

'use strict';

var ES = require('../').ES6;
var test = require('tape');

var forEach = require('foreach');
var is = require('object-is');
var debug = require('util').format;

var hasSymbols = typeof Symbol === 'function' && typeof Symbol.iterator === 'symbol';

var MAX_SAFE_INTEGER = Number.MAX_SAFE_INTEGER || Math.pow(2, 53) - 1;

var coercibleObject = { valueOf: function () { return 3; }, toString: function () { return 42; } };
var valueOfOnlyObject = { valueOf: function () { return 4; }, toString: function () { return {}; } };
var toStringOnlyObject = { valueOf: function () { return {}; }, toString: function () { return 7; } };
var uncoercibleObject = { valueOf: function () { return {}; }, toString: function () { return {}; } };
var objects = [{}, coercibleObject, toStringOnlyObject, valueOfOnlyObject];
var numbers = [0, -0, Infinity, -Infinity, 42];
var nonNullPrimitives = [true, false, 'foo', ''].concat(numbers);
var primitives = [undefined, null].concat(nonNullPrimitives);

test('ToPrimitive', function (t) {
	t.test('primitives', function (st) {
		var testPrimitive = function (primitive) {
			st.ok(is(ES.ToPrimitive(primitive), primitive), primitive + ' is returned correctly');
		};
		forEach(primitives, testPrimitive);
		st.end();
	});

	t.test('objects', function (st) {
		st.equal(ES.ToPrimitive(coercibleObject), 3, 'coercibleObject with no hint coerces to valueOf');
		st.ok(is(ES.ToPrimitive({}), '[object Object]'), '{} with no hint coerces to Object#toString');
		st.equal(ES.ToPrimitive(coercibleObject, Number), 3, 'coercibleObject with hint Number coerces to valueOf');
		st.ok(is(ES.ToPrimitive({}, Number), '[object Object]'), '{} with hint Number coerces to NaN');
		st.equal(ES.ToPrimitive(coercibleObject, String), 42, 'coercibleObject with hint String coerces to nonstringified toString');
		st.equal(ES.ToPrimitive({}, String), '[object Object]', '{} with hint String coerces to Object#toString');
		st.equal(ES.ToPrimitive(toStringOnlyObject), 7, 'toStringOnlyObject returns non-stringified toString');
		st.equal(ES.ToPrimitive(valueOfOnlyObject), 4, 'valueOfOnlyObject returns valueOf');
		st.throws(function () { return ES.ToPrimitive(uncoercibleObject); }, TypeError, 'uncoercibleObject throws a TypeError');
		st.end();
	});

	t.end();
});

test('ToBoolean', function (t) {
	t.equal(false, ES.ToBoolean(undefined), 'undefined coerces to false');
	t.equal(false, ES.ToBoolean(null), 'null coerces to false');
	t.equal(false, ES.ToBoolean(false), 'false returns false');
	t.equal(true, ES.ToBoolean(true), 'true returns true');

	t.test('numbers', function (st) {
		forEach([0, -0, NaN], function (falsyNumber) {
			st.equal(false, ES.ToBoolean(falsyNumber), 'falsy number ' + falsyNumber + ' coerces to false');
		});
		forEach([Infinity, 42, 1, -Infinity], function (truthyNumber) {
			st.equal(true, ES.ToBoolean(truthyNumber), 'truthy number ' + truthyNumber + ' coerces to true');
		});

		st.end();
	});

	t.equal(false, ES.ToBoolean(''), 'empty string coerces to false');
	t.equal(true, ES.ToBoolean('foo'), 'nonempty string coerces to true');

	t.test('objects', function (st) {
		forEach(objects, function (obj) {
			st.equal(true, ES.ToBoolean(obj), 'object coerces to true');
		});
		st.equal(true, ES.ToBoolean(uncoercibleObject), 'uncoercibleObject coerces to true');

		st.end();
	});

	t.end();
});

test('ToNumber', function (t) {
	t.ok(is(NaN, ES.ToNumber(undefined)), 'undefined coerces to NaN');
	t.ok(is(ES.ToNumber(null), 0), 'null coerces to +0');
	t.ok(is(ES.ToNumber(false), 0), 'false coerces to +0');
	t.equal(1, ES.ToNumber(true), 'true coerces to 1');

	t.test('numbers', function (st) {
		st.ok(is(NaN, ES.ToNumber(NaN)), 'NaN returns itself');
		forEach([0, -0, 42, Infinity, -Infinity], function (num) {
			st.equal(num, ES.ToNumber(num), num + ' returns itself');
		});
		forEach(['foo', '0', '4a', '2.0', 'Infinity', '-Infinity'], function (numString) {
			st.ok(is(+numString, ES.ToNumber(numString)), '"' + numString + '" coerces to ' + Number(numString));
		});
		st.end();
	});

	t.test('objects', function (st) {
		forEach(objects, function (object) {
			st.ok(is(ES.ToNumber(object), ES.ToNumber(ES.ToPrimitive(object))), 'object ' + object + ' coerces to same as ToPrimitive of object does');
		});
		st.throws(function () { return ES.ToNumber(uncoercibleObject); }, TypeError, 'uncoercibleObject throws');
		st.end();
	});

	t.test('binary literals', function (st) {
		st.equal(ES.ToNumber('0b10'), 2, '0b10 is 2');
		st.equal(ES.ToNumber({ toString: function () { return '0b11'; } }), 3, 'Object that toStrings to 0b11 is 3');

		st.equal(true, is(ES.ToNumber('0b12'), NaN), '0b12 is NaN');
		st.equal(true, is(ES.ToNumber({ toString: function () { return '0b112'; } }), NaN), 'Object that toStrings to 0b112 is NaN');
		st.end();
	});

	t.test('octal literals', function (st) {
		st.equal(ES.ToNumber('0o10'), 8, '0o10 is 8');
		st.equal(ES.ToNumber({ toString: function () { return '0o11'; } }), 9, 'Object that toStrings to 0o11 is 9');

		st.equal(true, is(ES.ToNumber('0o18'), NaN), '0o18 is NaN');
		st.equal(true, is(ES.ToNumber({ toString: function () { return '0o118'; } }), NaN), 'Object that toStrings to 0o118 is NaN');
		st.end();
	});

	t.test('signed hex numbers', function (st) {
		st.equal(true, is(ES.ToNumber('-0xF'), NaN), '-0xF is NaN');
		st.equal(true, is(ES.ToNumber(' -0xF '), NaN), 'space-padded -0xF is NaN');
		st.equal(true, is(ES.ToNumber('+0xF'), NaN), '+0xF is NaN');
		st.equal(true, is(ES.ToNumber(' +0xF '), NaN), 'space-padded +0xF is NaN');

		st.end();
	});

	t.test('trimming of whitespace and non-whitespace characters', function (st) {
		var whitespace = ' \t\x0b\f\xa0\ufeff\n\r\u2028\u2029\u1680\u180e\u2000\u2001\u2002\u2003\u2004\u2005\u2006\u2007\u2008\u2009\u200a\u202f\u205f\u3000';
		st.equal(0, ES.ToNumber(whitespace + 0 + whitespace), 'whitespace is trimmed');

		// Zero-width space (zws), next line character (nel), and non-character (bom) are not whitespace.
		var nonWhitespaces = {
			'\\u0085': '\u0085',
			'\\u200b': '\u200b',
			'\\ufffe': '\ufffe'
		};

		forEach(nonWhitespaces, function (desc, nonWS) {
			st.equal(true, is(ES.ToNumber(nonWS + 0 + nonWS), NaN), 'non-whitespace ' + desc + ' not trimmed');
		});

		st.end();
	});

	t.end();
});

test('ToInteger', function (t) {
	t.ok(is(0, ES.ToInteger(NaN)), 'NaN coerces to +0');
	forEach([0, Infinity, 42], function (num) {
		t.ok(is(num, ES.ToInteger(num)), num + ' returns itself');
		t.ok(is(-num, ES.ToInteger(-num)), '-' + num + ' returns itself');
	});
	t.equal(3, ES.ToInteger(Math.PI), 'pi returns 3');
	t.throws(function () { return ES.ToInteger(uncoercibleObject); }, TypeError, 'uncoercibleObject throws');
	t.end();
});

test('ToInt32', function (t) {
	t.ok(is(0, ES.ToInt32(NaN)), 'NaN coerces to +0');
	forEach([0, Infinity], function (num) {
		t.ok(is(0, ES.ToInt32(num)), num + ' returns +0');
		t.ok(is(0, ES.ToInt32(-num)), '-' + num + ' returns +0');
	});
	t.throws(function () { return ES.ToInt32(uncoercibleObject); }, TypeError, 'uncoercibleObject throws');
	t.ok(is(ES.ToInt32(0x100000000), 0), '2^32 returns +0');
	t.ok(is(ES.ToInt32(0x100000000 - 1), -1), '2^32 - 1 returns -1');
	t.ok(is(ES.ToInt32(0x80000000), -0x80000000), '2^31 returns -2^31');
	t.ok(is(ES.ToInt32(0x80000000 - 1), 0x80000000 - 1), '2^31 - 1 returns 2^31 - 1');
	forEach([0, Infinity, NaN, 0x100000000, 0x80000000, 0x10000, 0x42], function (num) {
		t.ok(is(ES.ToInt32(num), ES.ToInt32(ES.ToUint32(num))), 'ToInt32(x) === ToInt32(ToUint32(x)) for 0x' + num.toString(16));
		t.ok(is(ES.ToInt32(-num), ES.ToInt32(ES.ToUint32(-num))), 'ToInt32(x) === ToInt32(ToUint32(x)) for -0x' + num.toString(16));
	});
	t.end();
});

test('ToUint32', function (t) {
	t.ok(is(0, ES.ToUint32(NaN)), 'NaN coerces to +0');
	forEach([0, Infinity], function (num) {
		t.ok(is(0, ES.ToUint32(num)), num + ' returns +0');
		t.ok(is(0, ES.ToUint32(-num)), '-' + num + ' returns +0');
	});
	t.throws(function () { return ES.ToUint32(uncoercibleObject); }, TypeError, 'uncoercibleObject throws');
	t.ok(is(ES.ToUint32(0x100000000), 0), '2^32 returns +0');
	t.ok(is(ES.ToUint32(0x100000000 - 1), 0x100000000 - 1), '2^32 - 1 returns 2^32 - 1');
	t.ok(is(ES.ToUint32(0x80000000), 0x80000000), '2^31 returns 2^31');
	t.ok(is(ES.ToUint32(0x80000000 - 1), 0x80000000 - 1), '2^31 - 1 returns 2^31 - 1');
	forEach([0, Infinity, NaN, 0x100000000, 0x80000000, 0x10000, 0x42], function (num) {
		t.ok(is(ES.ToUint32(num), ES.ToUint32(ES.ToInt32(num))), 'ToUint32(x) === ToUint32(ToInt32(x)) for 0x' + num.toString(16));
		t.ok(is(ES.ToUint32(-num), ES.ToUint32(ES.ToInt32(-num))), 'ToUint32(x) === ToUint32(ToInt32(x)) for -0x' + num.toString(16));
	});
	t.end();
});

test('ToInt16', function (t) {
	t.ok(is(0, ES.ToInt16(NaN)), 'NaN coerces to +0');
	forEach([0, Infinity], function (num) {
		t.ok(is(0, ES.ToInt16(num)), num + ' returns +0');
		t.ok(is(0, ES.ToInt16(-num)), '-' + num + ' returns +0');
	});
	t.throws(function () { return ES.ToInt16(uncoercibleObject); }, TypeError, 'uncoercibleObject throws');
	t.ok(is(ES.ToInt16(0x100000000), 0), '2^32 returns +0');
	t.ok(is(ES.ToInt16(0x100000000 - 1), -1), '2^32 - 1 returns -1');
	t.ok(is(ES.ToInt16(0x80000000), 0), '2^31 returns +0');
	t.ok(is(ES.ToInt16(0x80000000 - 1), -1), '2^31 - 1 returns -1');
	t.ok(is(ES.ToInt16(0x10000), 0), '2^16 returns +0');
	t.ok(is(ES.ToInt16(0x10000 - 1), -1), '2^16 - 1 returns -1');
	t.end();
});

test('ToUint16', function (t) {
	t.ok(is(0, ES.ToUint16(NaN)), 'NaN coerces to +0');
	forEach([0, Infinity], function (num) {
		t.ok(is(0, ES.ToUint16(num)), num + ' returns +0');
		t.ok(is(0, ES.ToUint16(-num)), '-' + num + ' returns +0');
	});
	t.throws(function () { return ES.ToUint16(uncoercibleObject); }, TypeError, 'uncoercibleObject throws');
	t.ok(is(ES.ToUint16(0x100000000), 0), '2^32 returns +0');
	t.ok(is(ES.ToUint16(0x100000000 - 1), 0x10000 - 1), '2^32 - 1 returns 2^16 - 1');
	t.ok(is(ES.ToUint16(0x80000000), 0), '2^31 returns +0');
	t.ok(is(ES.ToUint16(0x80000000 - 1), 0x10000 - 1), '2^31 - 1 returns 2^16 - 1');
	t.ok(is(ES.ToUint16(0x10000), 0), '2^16 returns +0');
	t.ok(is(ES.ToUint16(0x10000 - 1), 0x10000 - 1), '2^16 - 1 returns 2^16 - 1');
	t.end();
});

test('ToInt8', function (t) {
	t.ok(is(0, ES.ToInt8(NaN)), 'NaN coerces to +0');
	forEach([0, Infinity], function (num) {
		t.ok(is(0, ES.ToInt8(num)), num + ' returns +0');
		t.ok(is(0, ES.ToInt8(-num)), '-' + num + ' returns +0');
	});
	t.throws(function () { return ES.ToInt8(uncoercibleObject); }, TypeError, 'uncoercibleObject throws');
	t.ok(is(ES.ToInt8(0x100000000), 0), '2^32 returns +0');
	t.ok(is(ES.ToInt8(0x100000000 - 1), -1), '2^32 - 1 returns -1');
	t.ok(is(ES.ToInt8(0x80000000), 0), '2^31 returns +0');
	t.ok(is(ES.ToInt8(0x80000000 - 1), -1), '2^31 - 1 returns -1');
	t.ok(is(ES.ToInt8(0x10000), 0), '2^16 returns +0');
	t.ok(is(ES.ToInt8(0x10000 - 1), -1), '2^16 - 1 returns -1');
	t.ok(is(ES.ToInt8(0x100), 0), '2^8 returns +0');
	t.ok(is(ES.ToInt8(0x100 - 1), -1), '2^8 - 1 returns -1');
	t.ok(is(ES.ToInt8(0x10), 0x10), '2^4 returns 2^4');
	t.end();
});

test('ToUint8', function (t) {
	t.ok(is(0, ES.ToUint8(NaN)), 'NaN coerces to +0');
	forEach([0, Infinity], function (num) {
		t.ok(is(0, ES.ToUint8(num)), num + ' returns +0');
		t.ok(is(0, ES.ToUint8(-num)), '-' + num + ' returns +0');
	});
	t.throws(function () { return ES.ToUint8(uncoercibleObject); }, TypeError, 'uncoercibleObject throws');
	t.ok(is(ES.ToUint8(0x100000000), 0), '2^32 returns +0');
	t.ok(is(ES.ToUint8(0x100000000 - 1), 0x100 - 1), '2^32 - 1 returns 2^8 - 1');
	t.ok(is(ES.ToUint8(0x80000000), 0), '2^31 returns +0');
	t.ok(is(ES.ToUint8(0x80000000 - 1), 0x100 - 1), '2^31 - 1 returns 2^8 - 1');
	t.ok(is(ES.ToUint8(0x10000), 0), '2^16 returns +0');
	t.ok(is(ES.ToUint8(0x10000 - 1), 0x100 - 1), '2^16 - 1 returns 2^8 - 1');
	t.ok(is(ES.ToUint8(0x100), 0), '2^8 returns +0');
	t.ok(is(ES.ToUint8(0x100 - 1), 0x100 - 1), '2^8 - 1 returns 2^16 - 1');
	t.ok(is(ES.ToUint8(0x10), 0x10), '2^4 returns 2^4');
	t.ok(is(ES.ToUint8(0x10 - 1), 0x10 - 1), '2^4 - 1 returns 2^4 - 1');
	t.end();
});

test('ToUint8Clamp', function (t) {
	t.ok(is(0, ES.ToUint8Clamp(NaN)), 'NaN coerces to +0');
	t.ok(is(0, ES.ToUint8Clamp(0)), '+0 returns +0');
	t.ok(is(0, ES.ToUint8Clamp(-0)), '-0 returns +0');
	t.ok(is(0, ES.ToUint8Clamp(-Infinity)), '-Infinity returns +0');
	t.throws(function () { return ES.ToUint8Clamp(uncoercibleObject); }, TypeError, 'uncoercibleObject throws');
	forEach([255, 256, 0x100000, Infinity], function (number) {
		t.ok(is(255, ES.ToUint8Clamp(number)), number + ' coerces to 255');
	});
	t.equal(1, ES.ToUint8Clamp(1.49), '1.49 coerces to 1');
	t.equal(2, ES.ToUint8Clamp(1.5), '1.5 coerces to 2, because 2 is even');
	t.equal(2, ES.ToUint8Clamp(1.51), '1.51 coerces to 2');

	t.equal(2, ES.ToUint8Clamp(2.49), '2.49 coerces to 2');
	t.equal(2, ES.ToUint8Clamp(2.5), '2.5 coerces to 2, because 2 is even');
	t.equal(3, ES.ToUint8Clamp(2.51), '2.51 coerces to 3');
	t.end();
});

test('ToString', function (t) {
	forEach(objects.concat(primitives), function (item) {
		t.equal(ES.ToString(item), String(item), 'ES.ToString(' + debug(item) + ') ToStrings to String(' + debug(item) + ')');
	});
	t.throws(function () { return ES.ToString(uncoercibleObject); }, TypeError, 'uncoercibleObject throws');
	if (hasSymbols) {
		t.throws(function () { return ES.ToString(Symbol.iterator); }, TypeError, debug(Symbol.iterator) + ' throws');
	}
	t.end();
});

test('ToObject', function (t) {
	t.throws(function () { return ES.ToObject(undefined); }, TypeError, 'undefined throws');
	t.throws(function () { return ES.ToObject(null); }, TypeError, 'null throws');
	forEach(numbers, function (number) {
		var obj = ES.ToObject(number);
		t.equal(typeof obj, 'object', 'number ' + number + ' coerces to object');
		t.equal(true, obj instanceof Number, 'object of ' + number + ' is Number object');
		t.ok(is(obj.valueOf(), number), 'object of ' + number + ' coerces to ' + number);
	});
	t.end();
});

test('RequireObjectCoercible', function (t) {
	t.equal(false, 'CheckObjectCoercible' in ES, 'CheckObjectCoercible -> RequireObjectCoercible in ES6');
	t.throws(function () { return ES.RequireObjectCoercible(undefined); }, TypeError, 'undefined throws');
	t.throws(function () { return ES.RequireObjectCoercible(null); }, TypeError, 'null throws');
	var doesNotThrow = function (value) {
		t.doesNotThrow(function () { return ES.RequireObjectCoercible(value); }, '"' + value + '" does not throw');
	};
	forEach(objects.concat(nonNullPrimitives), doesNotThrow);
	t.end();
});

test('IsCallable', function (t) {
	t.equal(true, ES.IsCallable(function () {}), 'function is callable');
	var nonCallables = [/a/g, {}, Object.prototype, NaN].concat(primitives);
	forEach(nonCallables, function (nonCallable) {
		t.equal(false, ES.IsCallable(nonCallable), nonCallable + ' is not callable');
	});
	t.end();
});

test('SameValue', function (t) {
	t.equal(true, ES.SameValue(NaN, NaN), 'NaN is SameValue as NaN');
	t.equal(false, ES.SameValue(0, -0), '+0 is not SameValue as -0');
	forEach(objects.concat(primitives), function (val) {
		t.equal(val === val, ES.SameValue(val, val), '"' + val + '" is SameValue to itself');
	});
	t.end();
});

test('SameValueZero', function (t) {
	t.equal(true, ES.SameValueZero(NaN, NaN), 'NaN is SameValueZero as NaN');
	t.equal(true, ES.SameValueZero(0, -0), '+0 is SameValueZero as -0');
	forEach(objects.concat(primitives), function (val) {
		t.equal(val === val, ES.SameValueZero(val, val), '"' + val + '" is SameValueZero to itself');
	});
	t.end();
});

test('ToPropertyKey', function (t) {
	forEach(objects.concat(primitives), function (value) {
		t.equal(ES.ToPropertyKey(value), String(value), 'ToPropertyKey(value) === String(value) for non-Symbols');
	});
	if (hasSymbols) {
		t.equal(ES.ToPropertyKey(Symbol.iterator), 'Symbol(Symbol.iterator)', 'ToPropertyKey(Symbol.iterator) === "Symbol(Symbol.iterator)"');
	}
	t.end();
});

test('ToLength', function (t) {
	t.throws(function () { return ES.ToLength(uncoercibleObject); }, TypeError, 'uncoercibleObject throws a TypeError');
	t.equal(3, ES.ToLength(coercibleObject), 'coercibleObject coerces to 3');
	t.equal(42, ES.ToLength('42.5'), '"42.5" coerces to 42');
	t.equal(7, ES.ToLength(7.3), '7.3 coerces to 7');
	forEach([-0, -1, -42, -Infinity], function (negative) {
		t.ok(is(0, ES.ToLength(negative)), negative + ' coerces to +0');
	});
	t.equal(MAX_SAFE_INTEGER, ES.ToLength(MAX_SAFE_INTEGER + 1), '2^53 coerces to 2^53 - 1');
	t.equal(MAX_SAFE_INTEGER, ES.ToLength(MAX_SAFE_INTEGER + 3), '2^53 + 2 coerces to 2^53 - 1');
	t.end();
});

test('IsArray', function (t) {
	t.equal(true, ES.IsArray([]), '[] is array');
	t.equal(false, ES.IsArray({}), '{} is not array');
	t.equal(false, ES.IsArray({ length: 1, 0: true }), 'arraylike object is not array');
	forEach(objects.concat(primitives), function (value) {
		t.equal(false, ES.IsArray(value), value + ' is not array');
	});
	t.end();
});

test('IsRegExp', function (t) {
	forEach([/a/g, new RegExp('a', 'g')], function (regex) {
		t.equal(true, ES.IsRegExp(regex), regex + ' is regex');
	});
	forEach(objects.concat(primitives), function (nonRegex) {
		t.equal(false, ES.IsRegExp(nonRegex), nonRegex + ' is not regex');
	});
	t.test('Symbol.match', { skip: !hasSymbols || !Symbol.match }, function (st) {
		var obj = {};
		obj[Symbol.match] = true;
		st.equal(true, ES.IsRegExp(obj), 'object with truthy Symbol.match is regex');

		var regex = /a/;
		regex[Symbol.match] = false;
		st.equal(false, ES.IsRegExp(regex), 'regex with falsy Symbol.match is not regex');

		st.end();
	});
	t.end();
});

test('IsPropertyKey', function (t) {
	forEach(numbers.concat(objects), function (notKey) {
		t.equal(false, ES.IsPropertyKey(notKey), notKey + ' is not property key');
	});
	t.equal(true, ES.IsPropertyKey('foo'), 'string is property key');
	if (hasSymbols) {
		t.equal(true, ES.IsPropertyKey(Symbol.iterator), 'Symbol.iterator is property key');
	}
	t.end();
});

test('IsInteger', function (t) {
	for (var i = -100; i < 100; i += 10) {
		t.equal(true, ES.IsInteger(i), i + ' is integer');
		t.equal(false, ES.IsInteger(i + 0.2), (i + 0.2) + ' is not integer');
	}
	t.equal(true, ES.IsInteger(-0), '-0 is integer');
	var notInts = objects.concat([Infinity, -Infinity, NaN, true, false, null, undefined, [], new Date()]);
	if (hasSymbols) { notInts.push(Symbol.iterator); }
	forEach(notInts, function (notInt) {
		t.equal(false, ES.IsInteger(notInt), ES.ToPropertyKey(notInt) + ' is not integer');
	});
	t.equal(false, ES.IsInteger(uncoercibleObject), 'uncoercibleObject is not integer');
	t.end();
});

test('IsExtensible', function (t) {
	forEach(objects, function (object) {
		t.equal(true, ES.IsExtensible(object), object + ' object is extensible');
	});
	forEach(primitives, function (primitive) {
		t.equal(false, ES.IsExtensible(primitive), primitive + ' is not extensible');
	});
	if (Object.preventExtensions) {
		t.equal(false, ES.IsExtensible(Object.preventExtensions({})), 'object with extensions prevented is not extensible');
	}
	t.end();
});

test('CanonicalNumericIndexString', function (t) {
	var throwsOnNonString = function (notString) {
		t.throws(function () { return ES.CanonicalNumericIndexString(notString); }, TypeError, notString + ' is not a string');
	};
	forEach(objects.concat(numbers), throwsOnNonString);
	t.ok(is(-0, ES.CanonicalNumericIndexString('-0')), '"-0" returns -0');
	for (var i = -50; i < 50; i += 10) {
		t.equal(i, ES.CanonicalNumericIndexString(String(i)), '"' + i + '" returns ' + i);
		t.equal(undefined, ES.CanonicalNumericIndexString(String(i) + 'a'), '"' + i + 'a" returns undefined');
	}
	t.end();
});

test('IsConstructor', function (t) {
	t.equal(true, ES.IsConstructor(function () {}), 'function is constructor');
	t.equal(false, ES.IsConstructor(/a/g), 'regex is not constructor');
	forEach(objects, function (object) {
		t.equal(false, ES.IsConstructor(object), object + ' object is not constructor');
	});

	try {
		var foo = Function('return class Foo {}')(); // eslint-disable-line no-new-func
		t.equal(ES.IsConstructor(foo), true, 'class is constructor');
	} catch (e) {
		t.comment('SKIP: class syntax not supported.');
	}
	t.end();
});

test('Call', function (t) {
	var receiver = {};
	var notFuncs = objects.concat(primitives).concat([/a/g, new RegExp('a', 'g')]);
	t.plan(notFuncs.length + 4);
	var throwsOnCall = function (notFunc) {
		t.throws(function () { return ES.Call(notFunc, receiver); }, TypeError, notFunc + ' (' + typeof notFunc + ') is not callable');
	};
	forEach(notFuncs, throwsOnCall);
	ES.Call(function (a, b) {
		t.equal(this, receiver, 'context matches expected');
		t.deepEqual([a, b], [1, 2], 'named args are correct');
		t.equal(arguments.length, 3, 'extra argument was passed');
		t.equal(arguments[2], 3, 'extra argument was correct');
	}, receiver, [1, 2, 3]);
	t.end();
});

test('GetV', function (t) {
	t.throws(function () { return ES.GetV({ 7: 7 }, 7); }, TypeError, 'Throws a TypeError if `P` is not a property key');
	var obj = { a: function () {} };
	t.equal(ES.GetV(obj, 'a'), obj.a, 'returns property if it exists');
	t.equal(ES.GetV(obj, 'b'), undefined, 'returns undefiend if property does not exist');
	t.end();
});

test('GetMethod', function (t) {
	t.throws(function () { return ES.GetMethod({ 7: 7 }, 7); }, TypeError, 'Throws a TypeError if `P` is not a property key');
	t.equal(ES.GetMethod({}, 'a'), undefined, 'returns undefined in property is undefined');
	t.equal(ES.GetMethod({ a: null }, 'a'), undefined, 'returns undefined if property is null');
	t.equal(ES.GetMethod({ a: undefined }, 'a'), undefined, 'returns undefined if property is undefined');
	var obj = { a: function () {} };
	t.throws(function () { ES.GetMethod({ a: 'b' }, 'a'); }, TypeError, 'throws TypeError if property exists and is not callable');
	t.equal(ES.GetMethod(obj, 'a'), obj.a, 'returns property if it is callable');
	t.end();
});

test('Get', function (t) {
	t.throws(function () { return ES.Get('a', 'a'); }, TypeError, 'Throws a TypeError if `O` is not an Object');
	t.throws(function () { return ES.Get({ 7: 7 }, 7); }, TypeError, 'Throws a TypeError if `P` is not a property key');

	var value = {};
	t.test('Symbols', { skip: !hasSymbols }, function (st) {
		var sym = Symbol('sym');
		var obj = {};
		obj[sym] = value;
		st.equal(ES.Get(obj, sym), value, 'returns property `P` if it exists on object `O`');
		st.end();
	});
	t.equal(ES.Get({ a: value }, 'a'), value, 'returns property `P` if it exists on object `O`');
	t.end();
});

test('Type', { skip: !hasSymbols }, function (t) {
	t.equal(ES.Type(Symbol.iterator), 'Symbol', 'Type(Symbol.iterator) is Symbol');
	t.end();
});

test('SpeciesConstructor', function (t) {
	t.throws(function () { ES.SpeciesConstructor(null); }, TypeError);
	t.throws(function () { ES.SpeciesConstructor(undefined); }, TypeError);

	var defaultConstructor = function Foo() {};

	t.equal(
		ES.SpeciesConstructor({ constructor: undefined }, defaultConstructor),
		defaultConstructor,
		'undefined constructor returns defaultConstructor'
	);

	t.throws(
		function () { return ES.SpeciesConstructor({ constructor: null }, defaultConstructor); },
		TypeError,
		'non-undefined non-object constructor throws'
	);

	var Bar = function Bar() {};
	var hasSpecies = hasSymbols && Symbol.species;
	if (hasSpecies) {
		Bar[Symbol.species] = null;
	}
	t.equal(
		ES.SpeciesConstructor(new Bar(), defaultConstructor),
		defaultConstructor,
		'undefined/null Symbol.species returns default constructor'
	);

	t.test('with Symbol.species', { skip: !hasSpecies }, function (st) {
		var Baz = function Baz() {};
		Baz[Symbol.species] = Bar;
		st.equal(
			ES.SpeciesConstructor(new Baz(), defaultConstructor),
			Bar,
			'returns Symbol.species constructor value'
		);

		Baz[Symbol.species] = {};
		st.throws(
			function () { ES.SpeciesConstructor(new Baz(), defaultConstructor); },
			TypeError,
			'throws when non-constructor non-null non-undefined species value found'
		);

		st.end();
	});
	t.end();
});