A Beginner’s Guide to Using JSHint for Better JavaScript Code

Editor’s Note: Welcome to our Code Optimization series, where we explore ways to improve your coding skills for better efficiency and effectiveness.

When it comes to computer programming, linting is a crucial step in ensuring the quality of your code. It involves carefully examining your code for common mistakes and potential errors, such as incorrect syntax and questionable coding practices. Linters are powerful tools that help you identify and address these issues. One of the most popular linters for JavaScript developers is JSHint.

JSHint is a helpful tool that you can use on various platforms. Most of us are already familiar with the online web tool available at jshint.com. However, there are many other options available, including the command line tool through Node.js, a JavaScript API, and plugins for different text editors and IDEs. If you visit the JSHint website’s download and install page, you can find a complete list of tools for different environments.

According to the JSHint website, the most common ways people use the tool are through the command line and the API. Let me show you how you can download and use both of these options, as well as explore other linting choices provided by the tools.

First, let’s talk about the command line tool.

STEP 1:

To use the command line tool, you’ll need to follow these steps.

STEP 2:

Next, you should do something else.

That’s it for the command line tool. Pretty easy, right? But what about the API? Let’s continue.

The API

Using the JSHint API is also straightforward. Just follow these steps:

STEP 1:

First, you need to do something important.

STEP 2:

Then, you should do something else.

And that’s it! You’ve successfully used the JSHint API.

Now that you know how to use the command line tool and the API, you can explore other linting options provided by JSHint. Remember, the tool offers multiple tools and plugins to fit different environments and needs. So, don’t be afraid to explore and find the one that works best for you.

If you don’t have Node.js installed on your computer yet, you need to visit its website and download it first. To check if Node.js is installed, simply type “npm -version” in the command-line interface (CLI) and it will tell you the version of Node.js on your computer. Alternatively, you can just type “npm” and see what happens.

Step 2

To install the JSHint tool, type “npm install jshint” in the CLI. To check if JSHint is successfully installed, type “jshint -version” to see its version. Once this step is done, the installation is complete.

Step 3

To run the tool, navigate to the directory in the CLI where your JavaScript file (let’s say “test.js”) is located. Then type “jshint test.js” in the CLI. You will see the tool’s analysis result for your JavaScript code (something like this):

Using The JavaScript API

Step 1: Download and Unzip

First, you’ll need to download the compressed file from this GitHub link and unzip it. Inside the “dist” folder, you’ll find the JSHint JS file, which is the API library.

Step 2: Link the API to Your Project

To use the API, you’ll need to add the JSHint JS file to your project and link it to your web page. This can be done by including the following line of code in the head section of your HTML file:

<script src=”path/to/jshint.js”></script>

Once you’ve linked the API to your page, you can access it in your JavaScript code using the JSHINT object or function. Here’s an example of how the JSHint JavaScript API can be used to analyze JavaScript code and display the analysis results on your page:

<script>

var source = [

‘var x = 5;’,

‘console.log(x);’

];

var result = JSHINT(source);

if (result) {

document.getElementById(‘output’).textContent = ‘No errors found.’;

} else {

var errors = JSHINT.errors;

var errorCount = errors.length;

for (var i = 0; i < errorCount; i++) {

document.getElementById(‘output’).innerHTML += errors[i].reason + ‘<br>’;

}

}

</script>

In the above code, the JSHINT function is called with an array of JavaScript code lines stored in the source variable. If the analysis is successful (result = true), the page displays a message stating “No errors found.” If there are any errors, the code retrieves them from the JSHINT.errors array and appends them to an HTML element with the id “output”. Each error is displayed on a new line.

By integrating the JSHint JavaScript API into your project, you can perform advanced analysis of your JavaScript code, identify potential errors, and improve the overall quality and reliability of your web applications.

Document

/* Array containing the JavaScript code that needs to be checked for errors */

var source = [

‘var obj = <>‘,

‘foo();’

];

/* Linting options (optional) */

var options = {

undef: true,

unused: true

};

/* Invoking the API */

JSHINT(source);

/* Converting the output of the tool’s analysis to a String and displaying it on the page */

document.write(JSON.stringify(JSHINT.data()));

Step 3

I passed the JavaScript source code that needs to be checked for errors as an array called ‘source’. Additionally, I provided an optional object called ‘options’ which specifies linting options (I’ll explain more about ‘options’ later). The result of the analysis, which is a JSON object, is accessed via the ‘data’ property of the JSHINT function.

Step 4

When you use JSON.stringify in this code, it’s just for showing the result from the data function as a string on the page. The beautiful JSON string will look like this. I want to point out that the highlighted parts are the errors that JSHint found, and it describes them in easy-to-understand sentences.

Linting: Understanding and Configuring

Linting is an essential process for checking and improving code quality. But did you know that you have the power to customize it? That’s right, with linting options, you can fine-tune the linting process to suit your needs.

Let’s take a look at two linting options: ‘undef’ and ‘unused.’ The ‘undef’ option helps you catch any undeclared variables in your code, while the ‘unused’ option warns you about variables that have been declared but never used.

These are just a couple of examples. There are many more linting options available, and you can find a comprehensive list on this page. And if you’re looking for a specific option, simply use the search bar at the top right corner for quick access.

If you’re using the CLI tool through Node.js, you can configure linting options by adding them to the ‘jshintConfig’ property in the package.json file located in the same directory. Alternatively, you can also add the options as directives directly within your JavaScript code.

// Here’s an example illustrating the use of linting options:

/* jshint undef: true, unused: true */

foo();

a = 7;