Best practices in writing clean Javascript code

Why is clean Javascript code so important? First, it makes your code easier for others to understand. This is a huge advantage, especially if you work in a team. Second, clean javascrip t code is easier to maintain and debug. When everything is well organized, it’s easier to find and fix bugs. In the following article, we will present best practices in writing clean and understandable javascript code.

1.Consistent formatting

Use consistent indentation, consistent spacing and naming conventions throughout your code. Popular conventions include CamelCase for variables and functions and kebab-case for filenames.
Example:

// Variables and functions in CamelCase
const userAge = 25;
const maxUserLimit = 100;

function calculateTotalPrice(itemPrice, quantity) {
    return itemPrice * quantity;
}

// Helper function, used in getUserDetails
function findUserById(userId) {
    // Example implementation
    const users = [
        { id: 1, name: 'Alice', age: 30 },
        { id: 2, name: 'Bob', age: 25 }
    ];
    return users.find(user => user.id === userId);
}

// Using indentation and spacing
function getUserDetails(userId) {
    if (!userId) {
        return null;
    }

    const user = findUserById(userId);
    if (!user) {
        return null;
    }

    return {
        id: user.id,
        name: user.name,
        age: user.age
    };
}

// File names in kebab-case
// example files: user-profile.js, calculate-total-price.js

2.Descriptive names of variables and functions:

Choose meaningful and descriptive names for variables, functions and classes. This makes your code easier to understand.

// Good variable name
const maxUserLimit = 100;
// Good function name
function generateReportData(reportType, startDate, endDate) { /* ... */ }

// Bad variable name
const x = 100;
// Bad function name
function foo(a, b) { /* ... */ }

Choosing descriptive names for variables and functions is key to keeping code readable and understandable. Good names clearly communicate the purpose and use of a piece of code, making it easier to maintain and develop later. In the example, the name maxUserLimit is clear and immediately indicates that the variable stores the maximum limit of users. Similarly, the generateReportData function makes it clear that its task is to generate data for a report. In contrast, names such as x and foo are non-descriptive and can lead to confusion and errors, as they do not suggest what their purpose is or what operations they perform. Using descriptive names is a simple but very effective way to improve code quality.

3. Add comments to explain blocks of code

Comments play a key role in writing good code. They make it easier to understand what a piece of code does and why it was written in a certain way.

Be sure to comment on all relevant parts of the code, not just those that may be difficult to understand. Well-placed comments can significantly speed up the debugging process and make future code modifications easier. If you are considering whether to add a comment, do so – there is no such thing as too many good comments.

Comments should also be clear and understandable to other developers. This will allow new team members to quickly understand the logic of the application, which will reduce the time it takes to introduce them to the project.

4.Write modular code that can be reused

Divide your code into smaller, reusable modules or functions. This promotes code reuse and helps manage complexity. Modularizing your code also prevents duplication – if you create a function that is universal you will be able to easily apply it to different parts of the project.

    5. Error handling:

    Dealing with errors is another best practice in maintaining clean and readable Javascript code. Implement error handling by using try…catch blocks where needed and appropriate. This will allow you to effectively manage all kinds of failures.

    Example:

    try {
        // Attempt to perform some action
        const data = fetchDataFromAPI();
        process(data);
    } catch (error) {
        // Log the error to the console
        console.error('An error occurred while fetching data from the API:', error);
        
        // Inform the user about the error
        alert('There was a problem fetching the data. Please try again later.');
    
        // Additional steps for specific errors
        if (error instanceof NetworkError) {
            // Handle network error
            console.warn('Network connection issue:', error.message);
        } else if (error instanceof ServerError) {
            // Handle server error
            console.warn('Server-side issue:', error.message);
        } else {
            // Handle other types of errors
            console.warn('Unknown error:', error.message);
        }
    }
    

    In this example, try attempts to execute the fetchDataFromAPI function and process the data using process. If an error occurs while performing either of these operations, it will be caught by a catch block, which will display an error message in the console and inform the user of the problem. In addition, different types of errors can be handled differently, allowing more precise responses to different situations.

    6. Organize the functions in the file according to the principle of gradually lowering the level of detail

    Higher level functions should be at the top of the file and lower levels below. This makes it easier to read the source code naturally. Example:

    // INCORRECT
    // "I need the full name for something..."
    function getFullName(user) {
      return `${user.firstName} ${user.lastName}`;
    }
    
    function sendWelcomeMessage(user) {
      // "uh, here"
      const fullName = getFullName(user);
      console.log(`Welcome, ${fullName}! We're glad to have you with us.`);
    }
    
    // CORRECT
    function sendWelcomeMessage(user) {
      // "I need the user's full name"
      const fullName = getFullName(user);
      console.log(`Welcome, ${fullName}! We're glad to have you with us.`);
    }
    
    // "I use this to send the welcome message"
    function getFullName(user) {
      return `${user.firstName} ${user.lastName}`;
    }
    

    In the example above, the sendWelcomeMessage function is above because it is more general and calls the getFullName function, which is more specific and is below. This organization of the code makes it more readable and understandable.

    7. Use libraries and frameworks

    Using libraries and frameworks is crucial for writing clean and readable JavaScript code. These tools help standardize your code by providing proven solutions and best practices, which significantly affects the quality of your code.

    Libraries provide a set of ready-made functions that can be easily implemented in a project, saving time and avoiding writing code from scratch. For example, the Lodash library offers numerous functions for data manipulation that are optimized for performance and compatibility. Using such off-the-shelf solutions prevents writing repetitive code and minimizes the risk of errors.

    Frameworks such as React, Angular and Vue.js impose a structured approach to building applications, which makes it easier to maintain code consistency. These frameworks offer a component-based programming model that promotes code reuse and modularity. This makes code clearer and more manageable, and new features can be added without creating chaos.

    FAQ – Frequently Asked Questions

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