Скачать или смотреть How to Sort an Array of Objects by Multiple Properties in JavaScript

Discover how to effectively sort an array of objects by multiple properties, including handling `null` values in JavaScript. Learn to maintain the expected order with concise code snippets.
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This video is based on the question https://stackoverflow.com/q/68965467/ asked by the user 'Juozas Miškinis' ( https://stackoverflow.com/u/10687510/ ) and on the answer https://stackoverflow.com/a/68965540/ provided by the user 'Viktor M' ( https://stackoverflow.com/u/16227915/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Introduction

Sorting objects is a common task in programming, especially when managing lists of items that have multiple properties. One particularly interesting challenge is to sort an array of objects not only by one property but multiple properties, while also managing cases where some values might be null.

In this post, we will explore how to sort an array of objects by due date and name. We'll address the complexity introduced by null values and provide an optimal solution that avoids iterating over the array multiple times.

The Problem

You might find yourself in a situation like this: you have an array of objects where each object has a name and a date due. The requirement is to sort these objects first by due date and then by name. However, due dates can be null. By default, this might lead to a mishmash of orderings unless properly handled.

Here’s the initial example array:

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

The goal is to ensure that objects with null due dates are sorted to the end of the list while also ensuring that those with actual due dates are sorted correctly by name when due dates are the same.

The Solution

To address sorting while accounting for null values, we can build a sorting function that handles all conditions we need. Here’s how we can accomplish this.

Step-by-Step Breakdown

Define the Sorting Functions: You’ll want two functions — one for sorting by name and the other for sorting by due date.

Handle null Values: Ensure that when both items being compared have null due dates, they should be sorted by their name, allowing for proper alphabetical ordering.

Implement the Combined Sort Function: Finally, combine the two sorting criteria. Here's the code:

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

How It Works

Sorting by Name: The sortByName function uses localeCompare, making it easy to handle names regardless of their case.

Handling Due Dates: The sortByDueDate function correctly checks for null values and defers to alphabetical sorting when necessary.

Combining Sort Criteria: The return statement first tries to sort by due date; if that doesn't resolve to a definitive order, it returns the result of the name sort.

Conclusion

Sorting an array of objects by multiple properties in JavaScript requires careful consideration, especially when handling special cases like null values. Utilizing a combined custom sorting function allows you to maintain a clean and efficient approach without needing multiple passes over the array.

This method ensures that you have the desired order of items, while also managing edge cases like null values effectively.

By mastering techniques like these, you can enhance the usability and maintainability of your code in everyday programming tasks!