Number Object

Creating Number

// Primitive
let number = 15;
console.log(number); //=> 15
console.log(typeof number); //=> number

// Number
let number = Number(15);
console.log(number); //=> 15
console.log(typeof number); //=> number

// OO
let number = new Number(15);
console.log(number); //=> [Number: 15]
console.log(typeof number); //=> object

let number = new Number(017);
console.log(number); //=> [Number: 15]
console.log(typeof number); //=> object

Number Object

NUMBER PROPERTIES

Number.MIN_SAFE_INTEGER

console.log(Number.MIN_SAFE_INTEGER); //=> -9007199254740991 = -(2ˆ53 - 1)

Number.MAX_SAFE_INTEGER

console.log(Number.MAX_SAFE_INTEGER); //=>  9007199254740991 =   2ˆ53 - 1

Number.MIN_VALUE

console.log(Number.MIN_VALUE); //=> 5e-324

Number.MAX_VALUE

console.log(Number.MAX_VALUE); //=> 1.7976931348623157e+308

Number.POSITIVE_INFINITY

console.log(Number.POSITIVE_INFINITY); //=> Infinity
console.log(Infinity); //=> Infinity
console.log(Infinity + 1); //=> Infinity
console.log(Math.pow(10, 1000)); //=> Infinity
console.log(1 / Infinity); //=> 0

Number.NEGATIVE_INFINITY

console.log(Number.NEGATIVE_INFINITY); //=> -Infinity
console.log(-Infinity); //=> -Infinity
console.log(Math.log(0)); //=> -Infinity

Number.NaN

console.log(Number.NaN) //=> NaN
console.log(NaN) //=> NaN
console.log(0/0) //=> NaN

NUMBER METHODS

Number.isInteger()

console.log(Number.isInteger(15)); //=> true

Number.isSafeInteger()

-(2^53 - 1) and 2^53 - 1

console.log(Number.isSafeInteger(15)); //=> true

Number.isFinite()

console.log(Number.isFinite(Infinity)); //=> false

Number.isNaN()

console.log(NaN == 0 / 0); //=> false
console.log(Number.isNaN(0 / 0)); //=> true
console.log(Number.isNaN(parseInt(1))); //=> false
console.log(Number.isNaN(parseInt('1'))); //=> false
console.log(Number.isNaN(parseInt('1a'))); //=> false
console.log(Number.isNaN(parseInt('a1'))); //=> true
console.log(Number.isNaN(parseInt(true))); //=> true

Number.parseInt() / parseInt()

console.log(parseInt(1)); //=> 1
console.log(parseInt('1')); //=> 1
console.log(parseInt('1a')); //=> 1

console.log(parseInt('a1')); //=> NaN
console.log(parseInt(0 / 0)); //=> NaN
console.log(parseInt(true)); //=> NaN
console.log(parseInt(undefined)); //=> NaN
console.log(parseInt(null)); //=> NaN

console.log('15' + 15); //=> 1515
console.log(parseInt('15') + 15); //=> 30
console.log(parseInt('12F')); //=> 12
console.log(parseInt('F12')); //=> NaN
console.log(parseInt('F')); //=> NaN
console.log(parseInt('F', 16)); //=> 15

Number.parseFloat() / parseFloat()

console.log(parseFloat(1.1)); //=> 1.1
console.log(parseFloat('1.1')); //=> 1.1
console.log(parseFloat('1.1a')); //=> 1.1

NUMBER INSTANCES

Number.prototype.toString()

console.log(15.toString(16))                  // SyntaxError
console.log(Number(15).toString(16))          //=> f
console.log(new Number(15).toString(16))      //=> f

let number = 15
console.log(number.toString(16))              //=> f

let number = Number(15)
console.log(number.toString(16))              //=> f

let number = new Number(15)
console.log(number.toString(16))              //=> f

console.log(Number(15).toString(2))           //=> 1111
console.log(Number(15).toString(8))           //=> 17
console.log(Number(15).toString(16))          //=> f
console.log(Number(15412341234).toString(32)) //=> ebabafi

Number.prototype.toExponential()

console.log(Number(2222.22222).toExponential());

// Number.prototype.toFixed()
console.log(Number(2222.22222).toFixed());
console.log(Number(2222.22222).toFixed(1));

// Number.prototype.toPrecision()
console.log(Number(2.22222222).toPrecision(3));
console.log(Number(2222.22222).toPrecision(1));
console.log(Number(2222.22222).toPrecision(5));

Reference