JavaScript reduce example

The reduce method in JavaScript is used to perform a reduction operation on an array. It allows you to iterate over the elements of an array and accumulate a single value based on those elements. Here are a few use cases for the reduce method:

JavaScript reduce example

Simple example code.

Summing or calculating the total: You can use reduce to calculate the sum of all numbers in an array or the total of any other numerical values.

const numbers = [1, 2, 3, 4, 5];

const sum = numbers.reduce((accumulator, currentValue) => {
  return accumulator + currentValue;
});

console.log(sum); // Output: 15

Finding the maximum or minimum value: You can use reduce to find the maximum or minimum value in an array.

const numbers = [5, 3, 9, 1, 7];

const max = numbers.reduce((accumulator, currentValue) => {
  return Math.max(accumulator, currentValue);
});

console.log(max); // Output: 9

Concatenating strings: You can use reduce to concatenate multiple strings in an array.

const fruits = ['apple', 'banana', 'cherry'];

const result = fruits.reduce((accumulator, currentValue) => {
  return accumulator + ', ' + currentValue;
});

console.log(result); // Output: apple, banana, cherry

Counting occurrences: You can use reduce to count the occurrences of specific values in an array.

const votes = ['yes', 'no', 'yes', 'yes', 'no', 'yes', 'no'];

const count = votes.reduce((accumulator, currentValue) => {
  accumulator[currentValue] = (accumulator[currentValue] || 0) + 1;
  return accumulator;
}, {});

console.log(count);

Output:

These are just a few examples of what you can achieve with the reduce method in JavaScript. It provides a flexible way to transform and aggregate data in arrays based on custom logic, making it a powerful tool for array manipulation.

Comment if you have any doubts or suggestions on this Js Reduce topic.

Note: The All JS Examples codes are tested on the Firefox browser and the Chrome browser.
OS: Windows 10
Code: HTML 5 Version

JavaScript reduce example