How to use Array map() Method In Javascript

Method 2: Using for loop

This method creates a new array with the return value of calling a function for every array element. This method calls the provided function once for each element in an array, with maintaining the order.

Syntax:

array.map(function(currentValue, index, arr), thisValue)

Parameters:

function(currentValue, index, arr): This parameter is required. It specifies a function to be run for each element in the array.
- currentValue: This parameter is required. It specifies the value of the current element.
- index: This parameter is optional. It specifies the array index of the current element.
- arr: This parameter is optional. It specifies the array object to which the current element belongs.
thisValue: This parameter is optional. it specifies a value to be passed to the function to be used as its “this” value. If this parameter is empty, the value “undefined” will be passed.

Example: This example uses the JavaScript Array map() Method to get the object’s index with a given property.

Javascript

let arrayObj = [{
    prop_1: 'val',
    prop_2: 'val_12',
    prop_3: 'val_13'
}, {
    prop_1: 'val',
    prop_2: 'val_22',
    prop_3: 'val_23'
}];
 
function GFG_Fun() {
    let prop = 'prop_2';
    let val = 'val_22';
    console.log("Index of prop = "
        + prop + " val = " + val +
        " is = " +
        arrayObj.map(function (e) {
            return e.prop_2;
        }).indexOf(val));
}
 
GFG_Fun();

Output

Index of prop = prop_2 val = val_22 is = 1

JavaScript Get the index of an object by its property

Given an object, the task is to get the object’s index from the array of objects of the given property name and property value using JavaScript. we’re going to discuss a few techniques.

Below are the following approaches:

Table of Content

Using Array map() Method
Using for loop
Using findIndex() Method
Using some() Method

Tags:

#javascript-object #JavaScript-Questions #JavaScript #Web Technologies