Convert Array to Object Based on Key

Introduction

In this lab, we will explore how to convert an array of objects into an object where each object's key is a specified property value of the original objects. We will achieve this by using the Array.prototype.reduce() method and object destructuring in JavaScript. This lab will help you gain a deeper understanding of how to manipulate and transform data in JavaScript.

Skills Graph

%%%%{init: {'theme':'neutral'}}%%%% flowchart RL javascript(("JavaScript")) -.-> javascript/AdvancedConceptsGroup(["Advanced Concepts"]) javascript(("JavaScript")) -.-> javascript/BasicConceptsGroup(["Basic 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") javascript/AdvancedConceptsGroup -.-> javascript/spread_rest("Spread and Rest Operators") subgraph Lab Skills javascript/variables -.-> lab-28160{{"Array to Object Based on Key"}} javascript/data_types -.-> lab-28160{{"Array to Object Based on Key"}} javascript/arith_ops -.-> lab-28160{{"Array to Object Based on Key"}} javascript/comp_ops -.-> lab-28160{{"Array to Object Based on Key"}} javascript/array_methods -.-> lab-28160{{"Array to Object Based on Key"}} javascript/higher_funcs -.-> lab-28160{{"Array to Object Based on Key"}} javascript/spread_rest -.-> lab-28160{{"Array to Object Based on Key"}} end

Converting an Array to an Object Based on a Specific Key

To convert an array into an object based on a specific key and exclude that key from each value, follow these steps:

Open the Terminal/SSH and type node to start practicing coding.
Use Array.prototype.reduce() to create an object from the provided array.
Use object destructuring to extract the value of the given key and the associated data, and then add the key-value pair to the object.

Here's an example implementation:

const indexOn = (arr, key) =>
  arr.reduce((obj, v) => {
    const { [key]: id, ...data } = v;
    obj[id] = data;
    return obj;
  }, {});

You can then use the function like this:

indexOn(
  [
    { id: 10, name: "apple" },
    { id: 20, name: "orange" }
  ],
  "id"
);
// { '10': { name: 'apple' }, '20': { name: 'orange' } }

Summary

Congratulations! You have completed the Array to Object Based on Key lab. You can practice more labs in LabEx to improve your skills.