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Learn how to filter objects from two arrays in JavaScript while retaining the original properties. A simple solution to programming problems involving arrays of objects.
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How to Get an Array of the Same Object from Two Arrays Using JavaScript

When dealing with arrays of objects in JavaScript, you may often find yourself needing to filter data based on certain criteria. One common scenario is wanting to filter an array of products based on selections made from another array—a task many developers encounter.

In this blog, we will explore a practical example where we maintain the key attributes (in this case, the quantity of products) from one array while filtering based on values from another array.

The Problem Statement

Imagine you have two arrays:

A global list of products. This array (let's call it state.Data) contains various products, each with a code and a quantity that is always greater than or equal to zero.

A selected list of products. This second array (let's refer to it as action.value.Data) also contains products with the same codes but with quantities set to zero.

Your task is to filter the state.Data array to retrieve only those products that exist in the action.value.Data array, while retaining their original quantities.

An Example to Illustrate

Here’s a clearer visual of what we have:

state.Data

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action.value.Data

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Desired Result

You want to achieve this result:

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

The Solution

The solution to this problem is straightforward but highly efficient. Here’s how you can achieve the desired filtering using JavaScript's array methods map and filter.

Step 1: Get the Keys

First, extract the codes from the action.value.Data array.

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

Step 2: Filter the Values

Next, filter the state.Data array by checking if the product codes are in the array of keys obtained from the previous step.

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

Simplified Complete Example

Here is the complete code that performs both steps concisely:

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

Conclusion

By using the filter and map methods, you can efficiently achieve your goal of filtering an array based on conditions from another array. This method ensures that you maintain the original quantities from the state.Data array while only keeping the matched products identified in the action.value.Data.

Remember, the beauty of JavaScript lies in its rich array manipulation capabilities, making such tasks both simple and elegant. Happy coding!