How to Delete Items from Arrays Inside Objects in Javascript

Learn how to manage and delete items from arrays inside objects using Javascript. This guide covers practical examples and solutions for common scenarios.
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How to Delete Items from Arrays Inside Objects in Javascript

Managing data structures like arrays and objects in Javascript can often be challenging, particularly when you need to modify nested elements. Today, we’ll tackle a common problem many developers face: how to delete items from an array within an object that is part of another array.

Our scenario focuses on a list of presents and their prices for different individuals. We want to achieve two main objectives:

Add a field sumP to each object that contains the total cost of presents for each individual.

If sumP exceeds the amount of money they have, we need to delete the most expensive present from their list until they are within budget.

Understanding the Base Structure

Before diving into the solution, let’s look at the data structure we’re dealing with.

Example Data

We have an array of individuals (presentsData), where each individual has:

A name.

A list of presents.

An amount of money available.

We also have another array (prices), which maps each present to its price.

Here’s how the data looks:

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

Step One: Add the sumP Field

The first goal is straightforward—we need to calculate the total cost of presents for each individual and add that as a new field named sumP. Here’s how you can achieve this:

Code Snippet

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

Explanation

Mapping Prices: We create a Map from the prices array, which makes it easier to look up the price of each present.

Calculating sumP: For each person in presentsData, we create a new object that includes the original properties plus the calculated sumP.

Step Two: Remove the Most Expensive Present

Now, we need to ensure if the total price of presents exceeds the available money, we will remove the most expensive present until the total is within budget.

Identifying the Most Expensive Present

We’ll create a helper function that identifies the most expensive present from the current list.

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

Updating the Results

Now, for each individual, we’ll check if sumP exceeds their money and then filter out the most expensive present if necessary.

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

Explanation

Looping Until Within Budget: We use a while loop to keep deleting the most expensive item until the sumP is less than or equal to the available money.

Updating Presents: Each time we delete a present, we also update the sumP accordingly.

Conclusion

With this approach, you can effectively manage arrays within objects in Javascript. Whether it's for deleting specific items based on conditions or adding new fields, understanding the underlying data structure and using helper functions can simplify the process significantly.

Feel free to experiment with the provided code snippets in your Javascript environment. Happy coding!