How to Change Data in a Nested JSON with Javascript using Lodash

Learn how to easily modify specific values in a nested JSON structure using Javascript and Lodash, while ensuring data integrity.
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How to Change Data in a Nested JSON with Javascript using Lodash

JSON (JavaScript Object Notation) is a popular format for representing structured data. It’s commonly used to transmit data between a server and a web application as an alternative to XML. However, working with nested JSON data can sometimes be challenging, especially when you want to modify specific values without affecting the original structure.

The Problem

Let’s say you have a JSON structure representing a list of employees, and you want to change the age of certain employees. For instance, if an employee's age is 33, you want to change it to 1. Here’s what your JSON looks like:

[[See Video to Reveal this Text or Code Snippet]]

Your objective is to create a new array that modifies the ages of John and Bob while leaving the others unchanged. The modified JSON should look like this:

[[See Video to Reveal this Text or Code Snippet]]

The Solution

To achieve this without modifying the original JSON structure, you can use JavaScript to create a deep copy of your data and then manipulate that copy. Here’s a step-by-step breakdown of how to implement this solution:

Step 1: Create a Copy of Your Data

Using JSON.stringify() to convert your JSON object to a string and then JSON.parse() to create a fresh copy from that string ensures you don't modify the original data.

Step 2: Use Array Methods to Modify the Copy

Once you have a copy, you can use the map() method to iterate through the array of employees and apply any changes needed.

Example Code

Here’s how you can accomplish this in JavaScript:

[[See Video to Reveal this Text or Code Snippet]]

Explanation of the Code

Deep Copy: The line var copy = JSON.parse(JSON.stringify(data)) clones the original JSON, ensuring that the original data remains unchanged during manipulation.

Mapping through Employees: The map() function is used to create a new array based on the existing one but with the specified modifications. Inside the map function, we check if the age equals 33, and if so, we set it to 1.

Final Thoughts

Using JavaScript's built-in features makes it fairly simple to manipulate nested JSON data while safeguarding the integrity of the original structure. This method keeps your code clean and efficient, and by leveraging functions like map(), you can easily implement complex transformations. Next time you face a similar challenge, remember this approach to changing values in your nested JSON using JavaScript!