Скачать или смотреть How to Replace an Object in an Array by Index Using Lodash

Discover how to effectively replace an object in an array based on its index in JavaScript using Lodash. Learn simple methods with practical code examples!
---
This video is based on the question https://stackoverflow.com/q/62514409/ asked by the user 'Reinard Carranceja' ( https://stackoverflow.com/u/9478890/ ) and on the answer https://stackoverflow.com/a/62515814/ provided by the user 'mankowitz' ( https://stackoverflow.com/u/1706744/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: Lodash - replace object in array with the same index

Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/l...
The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license.

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
How to Replace an Object in an Array by Index Using Lodash

Replacing an object in an array can sometimes be a tricky task, especially when you want to maintain the original index of the object. If you're using Lodash and trying to replace an object by its _id while keeping it in the same position, you may run into issues.

The Problem: Object Replacement in an Array

You may have experienced a common scenario where you need to update an existing object within an array but found that using _.unionBy caused the new object to be added at the start of the array instead of replacing the existing one at its corresponding index.

Example Code

Here’s an example that illustrates the issue:

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

In this code snippet, state.allStudents is an array of student objects, and students is the new object you want to insert in place of the existing one with the same _id.

The Solution: Using .findIndex and .splice

Instead of using _.unionBy, a more effective approach is to utilize the native JavaScript methods: .findIndex and .splice. These methods allow you to locate the index of the object you wish to replace and directly modify the array.

Step-by-Step Implementation

Find the Index:
Use .findIndex to locate the index of the existing object based on its _id. This method returns the index of the first element that meets the condition provided.

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

Check for Existence:
Ensure that the index returned isn't -1, which indicates that the object does exist in the array.

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

Replace the Object:
Use .splice to replace the object at the found index with the new object. The first parameter of .splice is the index, the second is the number of elements to remove (in this case, 1), and the third is the new item to insert.

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

Complete Code Example

Here’s how the complete code looks:

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

Conclusion

By using .findIndex and .splice, you can efficiently replace an object within an array without disrupting the original order of elements. This approach provides a cleaner and more effective solution than using _.unionBy for this specific task. Having the right methods at your disposal can simplify many operations in JavaScript!

Feel free to reach out if you have any more questions or need further clarification on this topic!