Lodash _.uniqWith() Array Method

Posted in lodash Tutorial

Updated on Feb 23, 2024

By Mari Selvan

👁️ 37 - Views

⏳ 4 mins

💬 1 Comment

Photo Credit to CodeToFun

🙋 Introduction

In the realm of JavaScript programming, managing arrays often involves handling duplicates.

Lodash, a powerful utility library, provides the _.uniqWith() method to simplify the process of creating a unique array based on custom comparison logic.

This method is a valuable tool for developers aiming to streamline data without relying on standard equality checks.

🧠 Understanding _.uniqWith()

The _.uniqWith() method in Lodash is designed to create a new array with unique values by utilizing a custom comparator function to determine equality between elements. This offers flexibility in handling complex data structures or custom objects where the default comparison might not suffice.

💡 Syntax

syntax.js

Copied

_.uniqWith(array, [comparator])

array: The array to process.
comparator: The custom function to compare values (default is a strict equality check).

📝 Example

Let's explore a practical example to illustrate the functionality of _.uniqWith():

example.js

Copied

// Include Lodash library (ensure it's installed via npm)
const _ = require('lodash');

const arrayWithDuplicates = [
    { id: 1, name: 'Alice' },
    { id: 2, name: 'Bob' },
    { id: 1, name: 'Alice' }, // Duplicate entry
    { id: 3, name: 'Charlie' },
];

const uniqueArray = _.uniqWith(arrayWithDuplicates, (a, b) => a.id === b.id);

console.log(uniqueArray);
// Output: [ { id: 1, name: 'Alice' }, { id: 2, name: 'Bob' }, { id: 3, name: 'Charlie' } ]

In this example, the arrayWithDuplicates is processed, and duplicates are removed based on a custom comparator function comparing the id property.

🏆 Best Practices

Implement a Custom Comparator:

To make the most of _.uniqWith(), implement a custom comparator function tailored to your data structure. This ensures accurate and targeted comparison for unique value determination.
example.js
Copied
```
const customComparator = (a, b) => a.property === b.property; // Customize as per your data structure

const uniqueData = _.uniqWith(dataArray, customComparator);
console.log(uniqueData);
```

Choose the Right Data Structure:

Consider the structure of your data and choose appropriate properties for comparison. This ensures that the custom comparator effectively identifies and removes duplicates.

example.js

Copied

const complexDataArray = [
    { id: 1, details: { name: 'John', age: 25 } },
    { id: 2, details: { name: 'Jane', age: 30 } },
    { id: 1, details: { name: 'John', age: 25 } }, // Duplicate entry
];

const uniqueComplexData = _.uniqWith(complexDataArray, (a, b) => a.id === b.id);
console.log(uniqueComplexData);

Understand Comparator Logic:

Be mindful of how the comparator logic operates, especially when dealing with nested objects or arrays. Ensure that the logic aligns with your uniqueness criteria.
example.js
Copied
```
const nestedArray = [
    [1, 2, 3],
    [4, 5, 6],
    [1, 2, 3], // Duplicate entry
];

const uniqueNestedArray = _.uniqWith(nestedArray, (a, b) => _.isEqual(a, b));
console.log(uniqueNestedArray);
```

📚 Use Cases

Unique Object Array:

_.uniqWith() is particularly useful when dealing with an array of objects, allowing you to create a unique array based on specific properties.
example.js
Copied
```
const uniqueUserArray = _.uniqWith(usersArray, (a, b) => a.id === b.id);
console.log(uniqueUserArray);
```
Complex Data Structures:

When working with complex data structures, such as nested objects or arrays, _.uniqWith() provides a way to deduplicate based on custom comparison logic.
example.js
Copied
```
const uniqueNestedData = _.uniqWith(nestedDataArray, (a, b) => _.isEqual(a, b));
console.log(uniqueNestedData);
```

🎉 Conclusion

The _.uniqWith() method in Lodash is a powerful tool for creating unique arrays with custom comparison logic. Whether dealing with simple arrays of primitive values or complex data structures, this method provides the flexibility needed to handle duplicates efficiently.

Explore the capabilities of _.uniqWith() and elevate your array manipulation in JavaScript to new heights. Embrace the versatility of Lodash for streamlined and customized data processing!