Mastering Array Reduction in JavaScript

Introduction

In this lab, we will be exploring the use of the Array.prototype.reduce() method to calculate the sum of two or more numbers/arrays. We will learn how to initialize an accumulator with a value of 0 and how to use the spread operator to pass an array as individual arguments. By the end of this lab, you will have a better understanding of how to use the reduce() method in JavaScript.

Skills Graph

%%%%{init: {'theme':'neutral'}}%%%% flowchart RL javascript(("`JavaScript`")) -.-> javascript/BasicConceptsGroup(["`Basic Concepts`"]) javascript(("`JavaScript`")) -.-> javascript/AdvancedConceptsGroup(["`Advanced Concepts`"]) javascript/BasicConceptsGroup -.-> javascript/variables("`Variables`") javascript/BasicConceptsGroup -.-> javascript/data_types("`Data Types`") javascript/BasicConceptsGroup -.-> javascript/arith_ops("`Arithmetic Operators`") javascript/BasicConceptsGroup -.-> javascript/comp_ops("`Comparison Operators`") javascript/AdvancedConceptsGroup -.-> javascript/higher_funcs("`Higher-Order Functions`") javascript/AdvancedConceptsGroup -.-> javascript/spread_rest("`Spread and Rest Operators`") subgraph Lab Skills javascript/variables -.-> lab-28633{{"`Mastering Array Reduction in JavaScript`"}} javascript/data_types -.-> lab-28633{{"`Mastering Array Reduction in JavaScript`"}} javascript/arith_ops -.-> lab-28633{{"`Mastering Array Reduction in JavaScript`"}} javascript/comp_ops -.-> lab-28633{{"`Mastering Array Reduction in JavaScript`"}} javascript/higher_funcs -.-> lab-28633{{"`Mastering Array Reduction in JavaScript`"}} javascript/spread_rest -.-> lab-28633{{"`Mastering Array Reduction in JavaScript`"}} end

Here's how to find the sum of an array

To find the sum of an array of numbers, follow these steps:

Open the Terminal/SSH and type node to start coding.

Use the Array.prototype.reduce() method to add each value to an accumulator, which should be initialized with a value of 0.

Here's the code you can use to find the sum of the array:

const sum = (...arr) => [...arr].reduce((acc, val) => acc + val, 0);

To test the sum function, use the following code examples:

sum(1, 2, 3, 4); // 10 sum(...[1, 2, 3, 4]); // 10

By following these steps, you can easily find the sum of an array of numbers using JavaScript.