Tutorials

Lodash _.endsWith() String Method

Posted in lodash Tutorial

Updated on Nov 21, 2024

By Mari Selvan

👁️ 27 - Views

⏳ 4 mins

💬 1 Comment

Photo Credit to CodeToFun

🙋 Introduction

In JavaScript, string manipulation is a common task, and having efficient tools can greatly simplify development. Lodash, a popular utility library, provides a variety of helpful functions for working with strings. Among these functions is _.endsWith(), which allows developers to easily check if a string ends with a specified target string or character.

This method offers a convenient and reliable solution for string validation and processing.

🧠 Understanding _.endsWith() Method

The _.endsWith() method in Lodash checks if a given string ends with the specified target string or character. This functionality is particularly useful for tasks such as file extension validation, URL parsing, or suffix checking.

💡 Syntax

The syntax for the _.endsWith() method is straightforward:

syntax.js

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_.endsWith(string, target, [position=string.length])

string: The string to search within.
target: The target string or character to check for.
position (Optional): The position within the string to search up to.

📝 Example

Let's dive into a simple example to illustrate the usage of the _.endsWith() method:

example.js

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const _ = require('lodash');

const str = 'Hello, world!';
const endsWithWorld = _.endsWith(str, 'world!');

console.log(endsWithWorld);
// Output: true

In this example, _.endsWith() checks if the string str ends with the target string world!, returning true.

🏆 Best Practices

When working with the _.endsWith() method, consider the following best practices:

Validate File Extensions:

Use _.endsWith() to validate file extensions, ensuring that uploaded files conform to expected formats.
example.js
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```
const fileName = 'document.pdf';
const isValidFile = _.endsWith(fileName, '.pdf');

console.log(isValidFile);
// Output: true
```

Check URL Endings:

Verify if a URL ends with a specific path or extension, aiding in URL parsing and validation.

example.js

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const url = 'https://example.com/page.html';
const isHtmlPage = _.endsWith(url, '.html');

console.log(isHtmlPage);
// Output: true

Suffix Checking:

Efficiently check if strings end with certain suffixes, facilitating data processing and validation.

example.js

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const items = ['apple', 'banana', 'kiwi'];
const endsWithI = items.filter(item => _.endsWith(item, 'i'));

console.log(endsWithI);
// Output: ['kiwi']

📚 Use Cases

File Type Validation:

_.endsWith() can be used to validate file types based on their extensions, ensuring compatibility and security in file uploads.

example.js

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const uploadedFile = /* ...fetch uploaded file object... */;
const isImageFile = _.endsWith(uploadedFile.name, '.jpg') || _.endsWith(uploadedFile.name, '.png');

console.log(isImageFile);

URL Routing:

When implementing URL routing logic, _.endsWith() can help identify specific paths or extensions, directing users to the appropriate resources.

example.js

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const requestedPath = /* ...extract requested path from URL... */;
if (_.endsWith(requestedPath, '.html')) {
    // Serve HTML page
} else if (_.endsWith(requestedPath, '.css')) {
    // Serve CSS file
} else {
    // Handle other cases
}

Data Filtering:

In data processing tasks, _.endsWith() can assist in filtering out records based on specific suffixes or endings.

example.js

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const data = /* ...fetch data from API or database... */;
const filteredData = data.filter(item => _.endsWith(item.url, '.pdf'));

console.log(filteredData);

🎉 Conclusion

The _.endsWith() method in Lodash provides a reliable solution for checking if a string ends with a specified target string or character. Whether validating file extensions, parsing URLs, or filtering data, this method offers convenience and efficiency in string manipulation tasks.

By adhering to best practices and exploring diverse use cases, you can harness the full potential of the _.endsWith() method in your Lodash projects.