5 Advanced JavaScript Functions You Can Use to Improve Your Code Quality

JavaScript is the de facto language for building modern web and mobile applications. It powers a wide range of projects, from simple websites to dynamic, interactive apps.

To create products that users will love and appreciate, it’s essential you write code that is not only functional but also efficient and easy to maintain. Clean JavaScript code is vital for the success of any web or mobile app, whether it’s a hobby side project or a complex commercial application.

Here are some helpful JavaScript functions that can significantly improve the quality of your project’s code.

1. Once Function

This higher-order once function wraps another function to ensure you can only call it a single time. It should silently ignore subsequent attempts to call the resulting function.

Consider a situation where you want to make HTTP API requests to fetch data from a database. You can attach the once function as a callback for an event listener function, so that it triggers once, and no more.

function once(fn) {
let done = false;
return function() {
return done ? undefined : ((done = true), fn.apply(this, arguments));

The once function takes a function as an argument and returns a new function that you can only call once. When you call the new function for the first time, it runs the original function with the given arguments and saves the result.

Any subsequent calls to the new function return the saved result without running the original function again.

By using the once function you can guarantee the code only sends one request, even if the user clicks the button several times. This avoids performance issues and bugs that may result from redundant requests.

2. Pipe Function

This pipe function lets you chain multiple functions together in a sequence. The functions in the sequence will take the result of the preceding function as the input and the last function in the sequence will compute the final result.

const pipe = (...fns) => x => fns.reduce((y, f) => f(y), x);

Pipe functions can improve the readability and modularity of code by allowing you to write complex processing logic concisely. This can make your code more understandable, and easier to maintain.

3. Map Function

The map function is a method of the built-in JavaScript Array class. It creates a new array by applying a callback function to each element of the original array.

It loops through each element in the input array, passes it as an input to the callback function, and inserts each result into a new array.

const numbers = [1, 2, 3, 4, 5];
const doubled = numbers.map(x => x * 2);

Generally, map functions eliminate the need for using loops in JavaScript, especially infinite ones—infinite loops can cause significant computational overhead, leading to performance issues in an application. This makes the codebase more concise and less error-prone.

4. Pick Function

This pick function lets you selectively extract specific properties from an existing object and generate a new object with those properties as the result of the computation.

For instance, consider a reports feature in an application, by utilizing the pick function, you can effortlessly customize different reports based on the desired user information by explicitly specifying the properties that you want to include in various reports.

const pick = (obj, keys) => keys.reduce((acc, key) => (key in obj && (acc[key] = obj[key]), acc), {});

The pick function takes an object and any number of keys as arguments. The keys represent the properties you want to select. It then returns a new object that contains only the properties of the original object with matching keys.

Essentially, a pick function can encapsulate complex filtering logic into a single function, making the code easier to understand and debug.

It can also promote code reusability, since you can reuse the pick function throughout your codebase, reducing code duplication.

5. Zip Function

This zip function combines arrays into a single array of tuples, matching corresponding elements from each input array.

const zip = (...arrays) => {
const maxLength = Math.min(...arrays.map(x => x.length));
return Array.from({ length: maxLength }).map((_, i) => {
return Array.from({ length: arrays.length }, (_, k) => arrays[k][i]);

This is especially useful if you need to combine data from multiple sources instantly, removing the need to write redundant code that would otherwise clutter your codebase.

JavaScript functions greatly improve the quality of your code by providing a simplified and compact way to handle a lot of the programming logic for both small and large codebases. By understanding and using these functions, you can write more efficient, readable, and maintainable applications.

Writing good code makes it possible to build products that not only solve a particular problem for end users, but do so in a way that’s easy to modify.

Source: MakeUseOf

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