Check if Array Has Many Matches

Introduction

In this lab, we will explore the concept of checking if an array has many matches using JavaScript. You will learn how to use the Array.prototype.filter() method in combination with a given function to find all matching array elements and then check if there are more than one such elements using the Array.prototype.length property. By the end of this lab, you will have a better understanding of how to manipulate arrays 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`") subgraph Lab Skills javascript/variables -.-> lab-28143{{"`Check if Array Has Many Matches`"}} javascript/data_types -.-> lab-28143{{"`Check if Array Has Many Matches`"}} javascript/arith_ops -.-> lab-28143{{"`Check if Array Has Many Matches`"}} javascript/comp_ops -.-> lab-28143{{"`Check if Array Has Many Matches`"}} javascript/higher_funcs -.-> lab-28143{{"`Check if Array Has Many Matches`"}} end

Function to Check if Array Has Multiple Matches

To check if an array has more than one value matching a given function, follow these steps:

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

Use Array.prototype.filter() in combination with fn to find all matching array elements.

Use Array.prototype.length to check if more than one element matches fn.

Here's the code you can use:

const hasMany = (arr, fn) => arr.filter(fn).length > 1;

And here are some examples:

hasMany([1, 3], (x) => x % 2); // true hasMany([1, 2], (x) => x % 2); // false