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
Consider the following members of the Number constructor:
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Property/method |
Description |
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A constant property (cannot be changed) that contains the maximum allowed number: > Number.MAX_VALUE;
1.7976931348623157e+308
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The smallest number you can work with in JavaScript: > Number.MIN_VALUE;
5e-324
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Contains the Not A Number number. Same as the global NaN: > Number.NaN;
NaN
NaN is not equal to anything including itself:
> Number.NaN === Number.NaN;
false
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Same as the global |
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Same as |
The Number.prototype members
Following are the members of the Number constructor:
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Property/method |
Description |
|
|
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"
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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"
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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"
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