TypeScript Array map() Method

The Array.map() is an inbuilt TypeScript function that creates a new array with the results of calling a provided function on every element in the array.

Syntax:

array.map(callback[, thisObject])

Parameters:

This method accepts two parameters as mentioned above and described below: 

• callback: This parameter is the function that produces an element of the new Array from an element of the current one.
• thisObject: This is the Object to use as this parameter when executing callback.

Return Value:

This method returns the created array. 

Example 1: Applying a Mathematical Function: In this example we creates a number[] array, applies Math.log to each element using map().

Output:

[
 2.3978952727983707,
 4.48863636973214,
 3.1354942159291497,
 1.9459101490553132,
 4.584967478670572
]

Example 2: Mapping Elements with Their Indices: In this example we uses map() to iterate over arr, squaring each value. For each element.

Output:

key : 0 value : 4
key : 1 value : 25
key : 2 value : 36
key : 3 value : 9
key : 4 value : 64
key : 5 value : 81