How to use Array.reduce() Method In Javascript

Using a Loop

Array.reduce() is a powerful method in JavaScript used to reduce the elements of an array to a single value. It executes a provided function for each value of the array and accumulates a single result.

Syntax:

Array.reduce(callbackFunction, initialValue)

Example: The below code explains the use of the reduce() method to get the index of the max value in an array of objects.

Javascript

function indexOfMax(arr, prop) {
    return arr.reduce(
        (maxIndex, current, currentIndex, array) => {
            return current[prop] > 
            array[maxIndex][prop] ? currentIndex : 
            maxIndex;
    }, 0);
}
 
const people = [
    { name: 'Alice', age: 30 },
    { name: 'Bob', age: 40 },
    { name: 'John', age: 35 }
];
 
const maxAgeIndex = 
    indexOfMax(people, 'age');
console.log("Index of person with maximum age:", 
    maxAgeIndex);

Output

Index of person with maximum age: 1

How to Get Index of the Max Value in Array of Objects ?

When dealing with arrays of objects in JavaScript, it’s common to need the index of the object with the maximum value based on a certain property.

Below are the approaches to get the index of the max value in an array of objects:

Table of Content

Using a Loop
Using Array.reduce() Method

Tags:

#JavaScript-Questions #JavaScript #Web Technologies

Using a Loop

How to use Array.reduce() Method In Javascript

Syntax:

Javascript

How to Get Index of the Max Value in Array of Objects ?

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