JavaScript Array map() Method
JavaScript Array ObjectExample
Return an array, whose elements are the square roots of the original array elements:
var numbers = [4, 9, 16, 25];
function myFunction() {
x = document.getElementById("demo")
x.innerHTML = numbers.map(Math.sqrt);
}
function myFunction() {
x = document.getElementById("demo")
x.innerHTML = numbers.map(Math.sqrt);
}
The output result is:
2,3,4,5
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Definition and Usage
The map() method returns a new array, whose elements are the values obtained by calling a function on the original array elements.
The map() method processes elements in order according to the original array element order.
Note:map() does not check empty arrays.
Note:map() does not change the original array.
Browser Support
The numbers in the table specify the first browser version that fully supports the method.
| Method | |||||
|---|---|---|---|---|---|
| map() | Yes | 9 | 1.5 | Yes | Yes |
Syntax
array.map(function(currentValue,index,arr), thisValue)
Parameter Details
| Parameter | Description | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| function(currentValue, index,arr) | Required. A function that will be executed for each element in the array. Function parameters:
|
||||||||
| thisValue | Optional. An object to use as "this" when executing the callback, passed to the function. If thisValue is omitted, or if null or undefined is passed, the callback function's this will be the global object. |
Technical Details
| Return value: | Returns a new array, whose elements are the values obtained by calling a function on the original array elements. |
|---|---|
| JavaScript Version: | 1.6 |
More Examples
Example
Multiply each element in the array by the value specified in the input field, and return a new array:
var numbers = [65, 44, 12, 4];
function multiplyArrayElement(num) {
return num * document.getElementById("multiplyWith").value;
}
function myFunction() {
document.getElementById("demo").innerHTML = numbers.map(multiplyArrayElement);
}
function multiplyArrayElement(num) {
return num * document.getElementById("multiplyWith").value;
}
function myFunction() {
document.getElementById("demo").innerHTML = numbers.map(multiplyArrayElement);
}
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