JavaScript Number Methods
These number methods can be used on all JavaScript numbers:
- toFixed():
- toPrecision()
- toString()
- parseFloat()
- isNaN()
- isFinite()
- Number.isInteger()
- Number.isNaN()
- Number.parseFloat()
- Number.parseInt()
toFixed():
Formats a number using fixed-point notation with a specified number of digits after the decimal point.
Example
const num = 3.14159; console.log(num.toFixed(2)); // Output: "3.14"
toPrecision():
Formats a number to a specified precision (total number of significant digits).
Example
const num = 3.14159; console.log(num.toPrecision(3)); // Output: "3.14"
toString():
Converts a number to a string, optionally specifying the radix (base) for numerical systems other than base 10.
Example
const num = 42; console.log(num.toString()); // Output: "42" console.log(num.toString(2)); // Output: "101010"
parseInt():
Parses a string and returns an integer. It takes an optional radix (base) parameter.
Example
console.log(parseInt("42")); // Output: 42
console.log(parseInt("1010", 2)); // Output: 10
parseFloat():
Parses a string and returns a floating-point number.
Example
console.log(parseFloat("3.14")); // Output: 3.14
isNaN():
Checks if a value is NaN (Not-a-Number).
Example
console.log(isNaN("Hello")); // Output: true
isFinite():
Checks if a value is a finite number (not NaN, Infinity, or -Infinity).
Example
console.log(isFinite(42)); // Output: true console.log(isFinite(Infinity)); // Output: false
Number.isInteger():
Checks if a value is an integer.
Example
console.log(Number.isInteger(42)); // Output: true console.log(Number.isInteger(3.14)); // Output: false
Number.isNaN():
Checks if a value is NaN.
Example
console.log(Number.isNaN("Hello")); // Output: false
console.log(Number.isNaN(NaN)); // Output: true
Number.parseFloat()):
Parses a string and returns a floating-point number.
Example
console.log(Number.parseFloat("3.14")); // Output: 3.14
Number.parseInt():
Parses a string and returns an integer.