How to Convert Flat Arrays to Nested JSON Objects in Angular Material Trees

Описание: Learn how to convert selected nodes from an Angular Material Tree into a structured nested JSON object with clear steps and code examples.
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How to Convert Flat Arrays to Nested JSON Objects in Angular Material Trees

In the world of front-end development, managing data effectively is crucial, especially when dealing with complex structures like trees. A common challenge for developers working with Angular Material Trees is converting a flat array of selected nodes into a nested JSON object. This guide will walk you through the solution, step by step.

The Problem

You have selected nodes represented as a flat array, like so:

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What you need is a hierarchical JSON structure that nests these items according to their levels. For example, the expected JSON format looks like this:

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The Solution

To solve the problem of converting the flat structure to a nested JSON object, we can break down the solution into three major phases:

Assign IDs and Parent IDs to each item.

Convert the Flat Array to a Tree Structure.

Transform the Tree Structure into a JSON Object.

Step 1: Applying Relationships

First, we need to assign each item an ID and a parentId to establish relationships based on their levels.

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Step 2: Converting to a Tree

Next, we turn our modified array into a tree structure. This is where we arrange items into hierarchical formats based on their parent IDs.

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

Step 3: Transforming the Tree to JSON

Finally, we will transform the tree structure into a nested JSON object. In this step, we'll ensure that the children of any item that is not expandable are collected into an array.

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Bringing It All Together

Now we will combine these functions to create our final function buildTreeObject that will execute all the steps in sequence:

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Example Usage

You can now test your function using the use cases provided in the original problem statement:

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Conclusion

By structuring your approach into these manageable steps, you can easily convert selected nodes from a flat array into a nested JSON object for your Angular Material Tree. This method not only streamlines the process but also enhances your application's data management capabilities. Happy coding!