Find Matching Keys in JavaScript Objects

Introduction

In this lab, we will explore how to find all the keys in a JavaScript object that match a given value. By using Object.keys() and Array.prototype.filter(), we can efficiently search through an object and return an array of keys that correspond to the provided value. This will be a valuable skill for any JavaScript developer working with complex data structures.

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/BasicConceptsGroup -.-> javascript/array_methods("`Array Methods`") javascript/AdvancedConceptsGroup -.-> javascript/higher_funcs("`Higher-Order Functions`") subgraph Lab Skills javascript/variables -.-> lab-28308{{"`Find Matching Keys`"}} javascript/data_types -.-> lab-28308{{"`Find Matching Keys`"}} javascript/arith_ops -.-> lab-28308{{"`Find Matching Keys`"}} javascript/comp_ops -.-> lab-28308{{"`Find Matching Keys`"}} javascript/array_methods -.-> lab-28308{{"`Find Matching Keys`"}} javascript/higher_funcs -.-> lab-28308{{"`Find Matching Keys`"}} end

Find Matching Keys

To find all the keys in an object that match a given value, follow these steps:

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

Use Object.keys() to get all the properties of the object.

Use Array.prototype.filter() to test each key-value pair and return all keys that are equal to the given value.

Here's an example function that implements this logic:

const findKeys = (obj, val) => Object.keys(obj).filter((key) => obj[key] === val);

You can use this function like this:

const ages = { Leo: 20, Zoey: 21, Jane: 20 }; findKeys(ages, 20); // [ 'Leo', 'Jane' ]