JavaScript NumberObject
Number Object
The Number object is a wrapper object for primitive numeric values.
Number creation method: new Number().
Syntax
var num = new Number(value);
Note:If a parameter value cannot be converted to a number, NaN (Not-a-Number) is returned.
Number Object Properties
| Property | Description |
|---|---|
| constructor | Returns a reference to the Number function that created this object. |
| MAX_VALUE | The largest representable number. |
| MIN_VALUE | The smallest representable number. |
| NEGATIVE_INFINITY | Negative infinity; returned on overflow. |
| NaN | Not-a-number value. |
| POSITIVE_INFINITY | Positive infinity; returned on overflow. |
| prototype | Allows you to add properties and methods to an object. |
Number Object Methods
| Method | Description |
|---|---|
| isFinite | Detects whether the specified parameter is infinity. |
| isInteger | Detects whether the specified parameter is an integer. |
| isNaN | Detects whether the specified parameter is NaN. |
| isSafeInteger | Detects whether the specified parameter is a safe integer. |
| toExponential(x) | Converts the value of an object to exponential notation. |
| toFixed(x) | Converts a number to a string, with a specified number of digits after the decimal point. |
| toLocaleString(locales, options) | Returns a string representation of the number in a specific locale. |
| toPrecision(x) | Formats a number to a specified length. |
| toString() | Converts a number to a string, using a specified base (radix). |
| valueOf() | Returns the primitive numeric value of a Number object. |
ES6 New Number Properties
ES6 added the following three Number object properties:
- EPSILON: Represents the difference between 1 and the smallest Number greater than 1 that is closest to 1.
- MIN_SAFE_INTEGER: Represents the smallest safe integer in JavaScript (
-(253 - 1))。 - MAX_SAFE_INTEGER: Represents the largest safe integer in JavaScript (
253 - 1）。
Examples
var x = Number.EPSILON;
var y = Number.MIN_SAFE_INTEGER;
var z = Number.MAX_SAFE_INTEGER;
Try it yourself »
ES6 New Number Methods
ES6 added the following two Number object methods:
- Number.isInteger(): Used to determine whether the given parameter is an integer.
- Number.isSafeInteger(): Determines whether the passed parameter value is a "safe integer".
Number.isInteger() returns true if the parameter is an integer.
Examples
Number.isInteger(10); //Returns true
Number.isInteger(10.5); //Returns false
Try it yourself »
Number.isSafeInteger() determines whether the passed parameter value is a "safe integer".
The safe integer range is-(253 - 1)到 253 - 1 integers between, inclusive.-(253 - 1)和 253 - 1。
Examples
Number.isSafeInteger(10); //Returns true
Number.isSafeInteger(12345678901234567890); //Returns false
Try it yourself »