Number

This creates number objects:

> var n = new Number(101);
> typeof n;
"object"
> n.valueOf();
101

The Number objects are not primitive objects, but if you use any Number.prototype method on a primitive number, the primitive will be converted to a Number object behind the scenes and the code will work.

> var n = 123;
> typeof n;
"number"
> n.toString();
"123"

Used without new, the Number constructor returns a primitive number.

> Number("101");
101
> typeof Number("101");
"number"
> typeof new Number("101");
"object"

Members of the Number constructor

Property/method	Description
Number.MAX_VALUE	A constant property (cannot be changed) that contains the maximum allowed number. > Number.MAX_VALUE; 1.7976931348623157e+308
Number.MIN_VALUE	The smallest number you can work with in JavaScript. > Number.MIN_VALUE; 5e-324
Number.NaN	Contains the Not A Number number. The same as the global NaN. > Number.NaN; NaN NaN is not equal to anything including itself. > Number.NaN === Number.NaN; false
Number.POSITIVE_INFINITY	The same as the global Infinity number.
Number.NEGATIVE_INFINITY	The same as -Infinity.

The Number.prototype members

Property/method	Description
toFixed(fractionDigits)	Returns a string with the fixed-point representation of the number. Rounds the returned value. > var n = new Number(Math.PI); > n.valueOf(); 3.141592653589793 > n.toFixed(3); "3.142"
toExponential(fractionDigits)	Returns a string with exponential notation representation of the number object. Rounds the returned value. > var n = new Number(56789); > n.toExponential(2); "5.68e+4"
toPrecision(precision)	String representation of a number object, either exponential or fixed-point, depending on the number object. > var n = new Number(56789); > n.toPrecision(2); "5.7e+4" > n.toPrecision(5); "56789" > n.toPrecision(4); "5.679e+4" > var n = new Number(Math.PI); > n.toPrecision(4); "3.142"