Lodash _.sortedIndexOf() Array Method

Posted in lodash Tutorial

Updated on Mar 11, 2024

By Mari Selvan

👁️ 31 - Views

⏳ 4 mins

💬 1 Comment

Photo Credit to CodeToFun

🙋 Introduction

In the realm of JavaScript programming, efficient searching and indexing within arrays are common tasks.

Lodash, a popular utility library, provides a range of helpful functions, and one such gem is the _.sortedIndexOf() method. This method is designed for arrays that are already sorted, offering an optimized way to find the index of a specified value.

🧠 Understanding _.sortedIndexOf()

The _.sortedIndexOf() method in Lodash is specifically crafted for sorted arrays. It performs a binary search to find the index of the first occurrence of a given value. This can be advantageous in scenarios where you're working with ordered datasets, as binary searches are more efficient than linear searches.

💡 Syntax

syntax.js

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_.sortedIndexOf(array, value)

array: The sorted array to search.
value: The value to find in the array.

📝 Example

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

example.js

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

const sortedArray = [1, 3, 5, 7, 9, 11, 13];
const targetValue = 7;

const indexOfValue = _.sortedIndexOf(sortedArray, targetValue);

console.log(indexOfValue);
// Output: 3

In this example, the sortedArray is searched for the value 7, and the method returns the index 3, which is the first occurrence of 7 in the sorted array.

🏆 Best Practices

Array Sorting:

Ensure that the input array is sorted before using _.sortedIndexOf(). If the array is not sorted, consider using _.indexOf() or sort the array first using _.sortBy() or other sorting methods.

example.js

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const unsortedArray = [13, 5, 1, 7, 9, 3, 11];
const targetValue = 7;

// Sort the array first
const sortedArray = _.sortBy(unsortedArray);
const indexOfValue = _.sortedIndexOf(sortedArray, targetValue);

console.log(indexOfValue);

Value Existence Check:

Before utilizing the method, check if the target value exists in the array. If the value is not present, the method will still return a valid index, potentially leading to unexpected results.

example.js

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const nonExistentValue = 8;
const indexOfNonExistentValue = _.sortedIndexOf(sortedArray, nonExistentValue);

if (indexOfNonExistentValue === -1) {
    console.log('Value not found in the array');
} else {
    console.log('Index of the value:', indexOfNonExistentValue);
}

📚 Use Cases

Efficient Searching in Sorted Data:

_.sortedIndexOf() is ideal for scenarios where you have a sorted array, and you need to efficiently find the index of a specific value. This is common in applications dealing with time-series data, numerical datasets, or any sorted collection.
example.js
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```
const timestampArray = /* ...fetch sorted timestamps from database or elsewhere... */;
const targetTimestamp = /* ...get target timestamp... */;

const indexOfTimestamp = _.sortedIndexOf(timestampArray, targetTimestamp);
console.log(indexOfTimestamp);
```

Optimizing Range Queries:

When working with sorted arrays, _.sortedIndexOf() can be employed to optimize range queries, providing the starting index for the range.

example.js

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const rangeStart = 5;
const rangeEnd = 10;

const startIndex = _.sortedIndexOf(sortedArray, rangeStart);
const endIndex = _.sortedIndexOf(sortedArray, rangeEnd);

const range = sortedArray.slice(startIndex, endIndex + 1);
console.log(range);

🎉 Conclusion

The _.sortedIndexOf() method in Lodash is a valuable addition to your toolkit when dealing with sorted arrays. Its efficiency in finding the index of a value in a sorted context makes it a powerful tool for tasks requiring fast and precise searching.

Explore the capabilities of _.sortedIndexOf() and leverage its benefits when working with ordered datasets. Enhance the performance of your array operations with Lodash!