How To Merge Objects In Javascript

need to merge twoith JavaScript, you may need to merge two or more objects into a single object. Merging objects is the process of combining their properties, and there are several ways to achieve this in JavaScript. In this blog post, we will explore three common methods to merge objects: using Object.assign(), the spread operator, and lodash library.

Method 1: Using Object.assign()

The Object.assign() method is a built-in JavaScript function that is used to copy the values of all enumerable properties from one or more source objects to a target object. It returns the target object, which now has the properties of the source objects.

Here’s an example:

    const object1 = { a: 1, b: 2 };
    const object2 = { b: 3, c: 4 };

    const mergedObject = Object.assign({}, object1, object2);
    console.log(mergedObject); // { a: 1, b: 3, c: 4 }
    

Note that if the source objects have properties with the same key, the value from the last source object will overwrite the previous one.

Method 2: Using the Spread Operator

The spread operator (…) is a more recent addition to JavaScript, introduced with ECMAScript 2015 (ES6). It can be used to merge objects by spreading the properties of the source objects into a new target object. This method is more concise and easier to read than using Object.assign().

Here’s an example:

    const object1 = { a: 1, b: 2 };
    const object2 = { b: 3, c: 4 };

    const mergedObject = { ...object1, ...object2 };
    console.log(mergedObject); // { a: 1, b: 3, c: 4 }
    

Similar to Object.assign(), the spread operator will also overwrite properties with the same key from the earlier object(s) with the values from the later object(s).

Method 3: Using Lodash

Lodash is a popular JavaScript utility library that provides several functions for working with arrays, objects, strings, and more. One of its functions, _.merge(), can be used to merge objects deeply, which means it will also merge nested objects instead of overwriting them.

To use Lodash, you need to install it in your project:

npm install lodash or yarn add lodash

Once installed, you can use it as follows:

    const _ = require('lodash');

    const object1 = { a: 1, b: { c: 2 } };
    const object2 = { b: { d: 3 }, e: 4 };

    const mergedObject = _.merge({}, object1, object2);
    console.log(mergedObject); // { a: 1, b: { c: 2, d: 3 }, e: 4 }
    

As you can see in the example above, _.merge() combined the nested properties of the b key together, instead of overwriting them.

Conclusion

In this blog post, we have looked at three different methods to merge objects in JavaScript: Object.assign(), the spread operator, and lodash. Depending on your needs and project requirements, you can choose the method that best fits your use case.