Скачать или смотреть How to Dynamically Push Columns to a New Array in JavaScript

Learn how to handle dynamic arrays in JavaScript by pushing specific columns based on keys. Discover an efficient way to extract and redefine object properties with straightforward examples.
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How to Dynamically Push Columns to a New Array in JavaScript

When working with JavaScript arrays and objects, you might encounter a situation where you need to extract specific properties from an array of objects dynamically. For instance, you may have a list of objects representing data, and you want to create a new array that contains only certain properties, which are specified in another array of keys.

In this guide, we will explore how to accomplish this effectively, using the example provided in the question. We'll start with the original setup and then move to a dynamic solution that handles varying keys.

The Problem Setup

Given the following JavaScript code representing an array of objects and an array of keys:

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

From this setup, you want to push specific properties into a new array based on the keys you provide.

Initial Solution

The initial approach you might take is to loop through the data array and push specific properties directly based on hard-coded keys. Here is how that can look:

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Output:

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While this works, it's not flexible. If you change the keys in the keys array, you would have to manually adjust your code. That's where dynamic handling comes into play.

A Dynamic Solution

To make our code more dynamic, we can utilize Array.prototype.map() and Object.fromEntries(). This approach allows us to map over the keys and create objects based on them dynamically.

Step-by-Step Breakdown

Define the Original Data and Keys:
Start with your original array of objects and the array of keys that you want to extract.

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

Map Through the Data:
Utilize the map() function to create a new array. For each object in data, map over the keys array to form key-value pairs.

Transform the Key-Value Pairs into Objects:
Use Object.fromEntries() to convert the key-value pairs into a new object for each original object.

Here’s how to do it in code:

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

Final Output

By using the code above, the output will dynamically change based on the keys you have provided:

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Example with Different Keys

If you want to change your keys to ['order', 'userid'], just adjust the keys array:

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

When you run the previous mapping code again, you'll get:

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

Conclusion

In summary, using map() and Object.fromEntries() in JavaScript allows you to dynamically push columns to a new array based on specified keys. This method enhances your code's flexibility and maintainability, especially when working with varying data structures.

By following this approach, you'll be able to handle changes in your data requirements without needing to frequently alter your code—making your life much easier as a developer!



Feel free to experiment with this method in your own projects. You'll find that it can save you a lot of time and confusion when dealing with dynamic data structures. Happy coding!