es6-shim/test/number.js

describe('Number', function () {
  var functionsHaveNames = (function foo() {}).name === 'foo';
  var ifFunctionsHaveNamesIt = functionsHaveNames ? it : xit;
  var ifShimIt = (typeof process !== 'undefined' && process.env.NO_ES6_SHIM) ? it.skip : it;

  var integers = [5295, -5295, -9007199254740991, 9007199254740991, 0, -0];
  var nonIntegers = [-9007199254741992, 9007199254741992, 5.9];
  var infinities = [Infinity, -Infinity];

  var valueOfThree = { valueOf: function () { return 3; } };
  var valueOfNaN = { valueOf: function () { return NaN; } };
  var valueOfThrows = { valueOf: function () { throw Object(17); } };
  var toStringThrows = { toString: function () { throw Object(42); } };
  var toPrimitiveThrows = {
    valueOf: function () { throw Object(17); },
    toString: function () { throw Object(42); }
  };

  var nonNumbers = [
    undefined,
    true,
    false,
    null,
    {},
    [],
    'str',
    '',
    valueOfThree,
    valueOfNaN,
    valueOfThrows,
    toStringThrows,
    toPrimitiveThrows,
    /a/g
  ];
  var expectTrue = function (item) {
    expect(item).to.equal(true);
  };
  var expectFalse = function (item) {
    expect(item).to.equal(false);
  };

  ifShimIt('is on the exported object', function () {
    var exported = require('../');
    expect(exported.Number).to.equal(Number);
  });

  describe('Number constants', function () {
    it('should have max safe integer', function () {
      expect(Number).to.have.property('MAX_SAFE_INTEGER');
      expect(Object.prototype.propertyIsEnumerable.call(Number, 'MAX_SAFE_INTEGER')).to.equal(false);
      expect(Number.MAX_SAFE_INTEGER).to.equal(Math.pow(2, 53) - 1);
    });

    it('should have min safe integer', function () {
      expect(Number).to.have.property('MIN_SAFE_INTEGER');
      expect(Object.prototype.propertyIsEnumerable.call(Number, 'MIN_SAFE_INTEGER')).to.equal(false);
      expect(Number.MIN_SAFE_INTEGER).to.equal(-Math.pow(2, 53) + 1);
    });

    it('should have epsilon', function () {
      expect(Number).to.have.property('EPSILON');
      expect(Object.prototype.propertyIsEnumerable.call(Number, 'EPSILON')).to.equal(false);
      expect(Number.EPSILON).to.equal(2.2204460492503130808472633361816e-16);
    });

    it('should have NaN', function () {
      expect(Number).to.have.property('NaN');
      expect(Object.prototype.propertyIsEnumerable.call(Number, 'NaN')).to.equal(false);
      expect(isNaN(Number.NaN)).to.equal(true);
    });

    it('should have MAX_VALUE', function () {
      expect(Number).to.have.property('MAX_VALUE');
      expect(Object.prototype.propertyIsEnumerable.call(Number, 'MAX_VALUE')).to.equal(false);
      expect(Number.MAX_VALUE).to.equal(1.7976931348623157e+308);
    });

    it('should have MIN_VALUE', function () {
      expect(Number).to.have.property('MIN_VALUE');
      expect(Object.prototype.propertyIsEnumerable.call(Number, 'MIN_VALUE')).to.equal(false);
      expect(Number.MIN_VALUE).to.equal(5e-324);
    });

    it('should have NEGATIVE_INFINITY', function () {
      expect(Number).to.have.property('NEGATIVE_INFINITY');
      expect(Object.prototype.propertyIsEnumerable.call(Number, 'NEGATIVE_INFINITY')).to.equal(false);
      expect(Number.NEGATIVE_INFINITY).to.equal(-Infinity);
    });

    it('should have POSITIVE_INFINITY', function () {
      expect(Number).to.have.property('POSITIVE_INFINITY');
      expect(Object.prototype.propertyIsEnumerable.call(Number, 'POSITIVE_INFINITY')).to.equal(false);
      expect(Number.POSITIVE_INFINITY).to.equal(Infinity);
    });
  });

  describe('.parseInt()', function () {
    if (!Object.prototype.hasOwnProperty.call(Number, 'parseInt')) {
      return it('exists', function () {
        expect(Number).to.have.property('parseInt');
      });
    }

    it('should work', function () {
      /* eslint-disable radix */
      expect(Number.parseInt('601')).to.equal(601);
      /* eslint-enable radix */
    });

    ifFunctionsHaveNamesIt('has the right name', function () {
      expect(Number.parseInt).to.have.property('name', 'parseInt');
    });

    it('is not enumerable', function () {
      expect(Number).ownPropertyDescriptor('parseInt').to.have.property('enumerable', false);
    });

    it('has the right arity', function () {
      // WebKit nightly had the wrong length; fixed in https://bugs.webkit.org/show_bug.cgi?id=143657
      expect(Number.parseInt).to.have.property('length', 2);
    });

    it('is the same object as the global parseInt', function () {
      // fixed in WebKit nightly in https://bugs.webkit.org/show_bug.cgi?id=143799#add_comment
      expect(Number.parseInt).to.equal(parseInt);
    });
  });

  describe('.parseFloat()', function () {
    if (!Object.prototype.hasOwnProperty.call(Number, 'parseFloat')) {
      return it('exists', function () {
        expect(Number).to.have.property('parseFloat');
      });
    }

    it('should work', function () {
      expect(Number.parseFloat('5.5')).to.equal(5.5);
    });

    ifFunctionsHaveNamesIt('has the right name', function () {
      expect(Number.parseFloat).to.have.property('name', 'parseFloat');
    });

    it('is not enumerable', function () {
      expect(Number).ownPropertyDescriptor('parseFloat').to.have.property('enumerable', false);
    });

    it('has the right arity', function () {
      expect(Number.parseFloat).to.have.property('length', 1);
    });
  });

  describe('.isFinite()', function () {
    if (!Object.prototype.hasOwnProperty.call(Number, 'isFinite')) {
      return it('exists', function () {
        expect(Number).to.have.property('isFinite');
      });
    }

    ifFunctionsHaveNamesIt('has the right name', function () {
      expect(Number.isFinite).to.have.property('name', 'isFinite');
    });

    it('is not enumerable', function () {
      expect(Number).ownPropertyDescriptor('isFinite').to.have.property('enumerable', false);
    });

    it('has the right arity', function () {
      expect(Number.isFinite).to.have.property('length', 1);
    });

    it('should work', function () {
      integers.map(Number.isFinite).forEach(expectTrue);
      infinities.map(Number.isFinite).forEach(expectFalse);
      expect(Number.isFinite(Infinity)).to.equal(false);
      expect(Number.isFinite(-Infinity)).to.equal(false);
      expect(Number.isFinite(NaN)).to.equal(false);
      expect(Number.isFinite(4)).to.equal(true);
      expect(Number.isFinite(4.5)).to.equal(true);
      expect(Number.isFinite('hi')).to.equal(false);
      expect(Number.isFinite('1.3')).to.equal(false);
      expect(Number.isFinite('51')).to.equal(false);
      expect(Number.isFinite(0)).to.equal(true);
      expect(Number.isFinite(-0)).to.equal(true);
      expect(Number.isFinite(valueOfThree)).to.equal(false);
      expect(Number.isFinite(valueOfNaN)).to.equal(false);
      expect(Number.isFinite(valueOfThrows)).to.equal(false);
      expect(Number.isFinite(toStringThrows)).to.equal(false);
      expect(Number.isFinite(toPrimitiveThrows)).to.equal(false);
    });

    it('should not be confused by type coercion', function () {
      nonNumbers.map(Number.isFinite).forEach(expectFalse);
    });
  });

  describe('.isInteger()', function () {
    if (!Object.prototype.hasOwnProperty.call(Number, 'isInteger')) {
      return it('exists', function () {
        expect(Number).to.have.property('isInteger');
      });
    }

    ifFunctionsHaveNamesIt('has the right name', function () {
      expect(Number.isInteger).to.have.property('name', 'isInteger');
    });

    it('is not enumerable', function () {
      expect(Number).ownPropertyDescriptor('isInteger').to.have.property('enumerable', false);
    });

    it('has the right arity', function () {
      expect(Number.isInteger).to.have.property('length', 1);
    });

    it('should be truthy on integers', function () {
      integers.map(Number.isInteger).forEach(expectTrue);
      expect(Number.isInteger(4)).to.equal(true);
      expect(Number.isInteger(4.0)).to.equal(true);
      expect(Number.isInteger(1801439850948)).to.equal(true);
    });

    it('should be false when the type is not number', function () {
      nonNumbers.forEach(function (thing) {
        expect(Number.isInteger(thing)).to.equal(false);
      });
    });

    it('should be false when NaN', function () {
      expect(Number.isInteger(NaN)).to.equal(false);
    });

    it('should be false when ∞', function () {
      expect(Number.isInteger(Infinity)).to.equal(false);
      expect(Number.isInteger(-Infinity)).to.equal(false);
    });

    it('should be false when number is not integer', function () {
      expect(Number.isInteger(3.4)).to.equal(false);
      expect(Number.isInteger(-3.4)).to.equal(false);
    });

    it('should be true when abs(number) is 2^53 or larger', function () {
      expect(Number.isInteger(Math.pow(2, 53))).to.equal(true);
      expect(Number.isInteger(Math.pow(2, 54))).to.equal(true);
      expect(Number.isInteger(-Math.pow(2, 53))).to.equal(true);
      expect(Number.isInteger(-Math.pow(2, 54))).to.equal(true);
    });

    it('should be true when abs(number) is less than 2^53', function () {
      var safeIntegers = [0, 1, Math.pow(2, 53) - 1];
      safeIntegers.forEach(function (integer) {
        expect(Number.isInteger(integer)).to.equal(true);
        expect(Number.isInteger(-integer)).to.equal(true);
      });
    });
  });

  describe('.isSafeInteger()', function () {
    if (!Object.prototype.hasOwnProperty.call(Number, 'isSafeInteger')) {
      return it('exists', function () {
        expect(Number).to.have.property('isSafeInteger');
      });
    }

    ifFunctionsHaveNamesIt('has the right name', function () {
      expect(Number.isSafeInteger).to.have.property('name', 'isSafeInteger');
    });

    it('is not enumerable', function () {
      expect(Number).ownPropertyDescriptor('isSafeInteger').to.have.property('enumerable', false);
    });

    it('has the right arity', function () {
      expect(Number.isSafeInteger).to.have.property('length', 1);
    });

    it('should be truthy on integers', function () {
      integers.map(Number.isSafeInteger).forEach(expectTrue);
      expect(Number.isSafeInteger(4)).to.equal(true);
      expect(Number.isSafeInteger(4.0)).to.equal(true);
      expect(Number.isSafeInteger(1801439850948)).to.equal(true);
    });

    it('should be false when the type is not number', function () {
      nonNumbers.forEach(function (thing) {
        expect(Number.isSafeInteger(thing)).to.equal(false);
      });
    });

    it('should be false when NaN', function () {
      expect(Number.isSafeInteger(NaN)).to.equal(false);
    });

    it('should be false when ∞', function () {
      expect(Number.isSafeInteger(Infinity)).to.equal(false);
      expect(Number.isSafeInteger(-Infinity)).to.equal(false);
    });

    it('should be false when number is not integer', function () {
      expect(Number.isSafeInteger(3.4)).to.equal(false);
      expect(Number.isSafeInteger(-3.4)).to.equal(false);
    });

    it('should be false when abs(number) is 2^53 or larger', function () {
      expect(Number.isSafeInteger(Math.pow(2, 53))).to.equal(false);
      expect(Number.isSafeInteger(Math.pow(2, 54))).to.equal(false);
      expect(Number.isSafeInteger(-Math.pow(2, 53))).to.equal(false);
      expect(Number.isSafeInteger(-Math.pow(2, 54))).to.equal(false);
    });

    it('should be true when abs(number) is less than 2^53', function () {
      var safeIntegers = [0, 1, Math.pow(2, 53) - 1];
      safeIntegers.forEach(function (integer) {
        expect(Number.isSafeInteger(integer)).to.equal(true);
        expect(Number.isSafeInteger(-integer)).to.equal(true);
      });
    });
  });

  describe('.isNaN()', function () {
    if (!Object.prototype.hasOwnProperty.call(Number, 'isNaN')) {
      return it('exists', function () {
        expect(Number).to.have.property('isNaN');
      });
    }

    ifFunctionsHaveNamesIt('has the right name', function () {
      expect(Number.isNaN).to.have.property('name', 'isNaN');
    });

    it('is not enumerable', function () {
      expect(Number).ownPropertyDescriptor('isNaN').to.have.property('enumerable', false);
    });

    it('has the right arity', function () {
      expect(Number.isNaN).to.have.property('length', 1);
    });

    it('should be truthy only on NaN', function () {
      integers.concat(nonIntegers).map(Number.isNaN).forEach(expectFalse);
      nonNumbers.map(Number.isNaN).forEach(expectFalse);
      expect(Number.isNaN(NaN)).to.equal(true);
      expect(Number.isNaN(0 / 0)).to.equal(true);
      expect(Number.isNaN(Number('NaN'))).to.equal(true);
      expect(Number.isNaN(4)).to.equal(false);
      expect(Number.isNaN(4.5)).to.equal(false);
      expect(Number.isNaN('hi')).to.equal(false);
      expect(Number.isNaN('1.3')).to.equal(false);
      expect(Number.isNaN('51')).to.equal(false);
      expect(Number.isNaN(0)).to.equal(false);
      expect(Number.isNaN(-0)).to.equal(false);
      expect(Number.isNaN(valueOfThree)).to.equal(false);
      expect(Number.isNaN(valueOfNaN)).to.equal(false);
      expect(Number.isNaN(valueOfThrows)).to.equal(false);
      expect(Number.isNaN(toStringThrows)).to.equal(false);
      expect(Number.isNaN(toPrimitiveThrows)).to.equal(false);
    });
  });

  describe('constructor', function () {
    it('behaves like the builtin', function () {
      expect((1).constructor).to.equal(Number);
      expect(Number()).to.equal(0);
    });

    describe('strings in the constructor', function () {
      it('works on normal literals', function () {
        expect(Number('1')).to.equal(+'1');
        expect(Number('1.1')).to.equal(+'1.1');
        expect(Number('0xA')).to.equal(0xA);
      });
    });

    describe('when called with a receiver', function () {
      it('returns a primitive when called with a primitive receiver', function () {
        expect((1).constructor(2)).to.equal(2);
        expect((1).constructor.call(null, 3)).to.equal(3);
        expect(Object(1).constructor.call(null, 5)).to.equal(5);
      });

      it('returns a primitive when called with a different number as an object receiver', function () {
        expect(Object(1).constructor(6)).to.equal(6);
        expect(Object(1).constructor.call(Object(1), 7)).to.equal(7);
      });

      it('returns a primitive when called with the same number as an object receiver', function () {
        expect(Object(1).constructor.call(Object(8), 8)).to.equal(8);
      });
    });

    it('works with boxed primitives', function () {
      expect(1 instanceof Number).to.equal(false);
      expect(Object(1) instanceof Number).to.equal(true);
    });

    it('works with `new`', function () {
      /* eslint-disable no-new-wrappers */
      var one = new Number('1');
      var a = new Number('0xA');
      /* eslint-enable no-new-wrappers */

      expect(+one).to.equal(1);
      expect(one instanceof Number).to.equal(true);
      expect(+a).to.equal(0xA);
      expect(a instanceof Number).to.equal(true);
    });

    it('works with binary literals in string form', function () {
      expect(Number('0b1')).to.equal(1);
      expect(Number(' 0b1')).to.equal(1);
      expect(Number('0b1 ')).to.equal(1);

      expect(Number('0b10')).to.equal(2);
      expect(Number(' 0b10')).to.equal(2);
      expect(Number('0b10 ')).to.equal(2);

      expect(Number('0b11')).to.equal(3);
      expect(Number(' 0b11')).to.equal(3);
      expect(Number('0b11 ')).to.equal(3);

      expect(Number({
        toString: function () { return '0b100'; },
        valueOf: function () { return '0b101'; }
      })).to.equal(5);
    });

    it('works with octal literals in string form', function () {
      expect(Number('0o7')).to.equal(7);
      expect(Number('0o10')).to.equal(8);
      expect(Number('0o11')).to.equal(9);
      expect(Number({
        toString: function () { return '0o12'; },
        valueOf: function () { return '0o13'; }
      })).to.equal(11);
    });

    it('should produce NaN', function () {
      expect(String(Number('0b12'))).to.equal('NaN');
      expect(String(Number('0o18'))).to.equal('NaN');
      expect(String(Number('0x1g'))).to.equal('NaN');
      expect(String(Number('+0b1'))).to.equal('NaN');
      expect(String(Number('+0o1'))).to.equal('NaN');
      expect(String(Number('+0x1'))).to.equal('NaN');
      expect(String(Number('-0b1'))).to.equal('NaN');
      expect(String(Number('-0o1'))).to.equal('NaN');
      expect(String(Number('-0x1'))).to.equal('NaN');
    });

    it('should work with well formed and poorly formed objects', function () {
      expect(String(Number({}))).to.equal('NaN');
      expect(String(Number({ valueOf: '1.1' }))).to.equal('NaN');
      expect(Number({ valueOf: '1.1', toString: function () { return '2.2'; } })).to.equal(2.2);
      expect(Number({ valueOf: function () { return '1.1'; }, toString: '2.2' })).to.equal(1.1);
      expect(Number({
        valueOf: function () { return '1.1'; },
        toString: function () { return '2.2'; }
      })).to.equal(1.1);
      expect(String(Number({ valueOf: function () { return '-0x1a2b3c'; } }))).to.equal('NaN');
      expect(String(Number({ toString: function () { return '-0x1a2b3c'; } }))).to.equal('NaN');
      expect(Number({ valueOf: function () { return '0o12345'; } })).to.equal(5349);
      expect(Number({ toString: function () { return '0o12345'; } })).to.equal(5349);
      expect(Number({ valueOf: function () { return '0b101010'; } })).to.equal(42);
      expect(Number({ toString: function () { return '0b101010'; } })).to.equal(42);
    });

    it('should work with correct whitespaces', function () {
      // Zero-width space (zws), next line character (nel), and non-character (bom) are not whitespace.
      var nonWhitespaces = ['\u0085', '\u200b', '\ufffe'];

      expect(String(Number(nonWhitespaces[0] + '0' + nonWhitespaces[0]))).to.equal('NaN');
      expect(String(Number(nonWhitespaces[1] + '1' + nonWhitespaces[1]))).to.equal('NaN');
      expect(String(Number(nonWhitespaces[2] + '2' + nonWhitespaces[2]))).to.equal('NaN');
    });

    it.skip('it works with updated unicode values', function () {
      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';

      expect(String(Number(whitespace + '3' + whitespace))).to.equal('3');
    });
  });
});