Find Matching Keys

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.

Find Matching Keys

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

1. Open the Terminal/SSH and type node to start practicing coding.
2. Use Object.keys() to get all the properties of the object.
3. 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' ]

Summary

Congratulations! You have completed the Find Matching Keys lab. You can practice more labs in LabEx to improve your skills.