3 Ways To Detect Circular Dependencies In JavaScript Projects
How to Prevent Circular Dependencies?
Circular dependencies are like a tricky puzzle where different parts of your code rely too much on each other. This can make your code hard to understand, change, or even break without you realizing it. It’s like having a tangled web that’s tough to untie. Finding and fixing these loops is important to keep your project running smoothly. This article explores three easy ways to spot and sort out these circular dependencies, making your JavaScript project cleaner and more trouble-free.
Circular Dependencies
Circular dependencies in JavaScript can be like a chicken-and-egg situation. Imagine you’re building a web application for an online store. You have a Product module that handles product details and a Cart module for the shopping cart functionality. The Product module needs to update the Cart when a product is added, and the Cart needs product information from the Product module to display items in the Cart.
// Product.js
const Cart = require('./Cart');
function Product(name, price) {
this.name = name;
this.price = price;
}
Product.prototype.addToCart = function() {
Cart.addProduct(this); // Adding this product to the Cart
}
module.exports = Product;
// Cart.js
const Product = require('./Product');
let productsInCart = [];
const Cart = {
addProduct: function(product) {
productsInCart.push(product);
console.log(`${product.name} added to cart`);
},
displayCart: function() {
return productsInCart.map(p => `${p.name}: $${p.price}`).join(', ');
}
}
module.exports = Cart;
This situation is known as circular dependency, and it introduces several complications to your code:
- Maintainability: When modules are closely intertwined, changing one part often requires changes in others, leading to a higher chance of bugs.
- Testing: Testing becomes more challenging as each module is not isolated. You might need to load multiple modules to test just one function.
- Tight Coupling: The modules depend heavily on each other, reducing flexibility.
- Initialization Issues: With circular dependencies, there’s a risk that a module might try to use another module that hasn’t been fully loaded yet. This can lead to errors or incomplete initialization, causing the application to behave unpredictably or crash.
- Impact on Performance: Circular dependencies can cause memory leaks or inefficient execution paths, which can degrade your application’s performance.
- Scalability Concerns: As your application grows, circular dependencies can make it more difficult to scale the codebase. Adding new features or scaling existing ones becomes harder when the codebase is riddled with complex interdependencies.
How Can You Prevent a Circular Dependency?
As explained above, circular dependencies can become a real headache for developers. Luckily, there are tools and techniques available to detect and resolve these dependencies.
Here are three effective methods: GitHub Actions, ESLint, and Bit.
1. GitHub Actions
GitHub Actions is a CI/CD platform that allows you to automate your build, test, and deployment pipeline directly from your GitHub repository. It allows you to create workflows that automatically execute on specific triggers like push or pull requests. You can use GitHub Actions to detect circular dependencies by integrating tools or scripts into your workflow. For example:
- Madge: Command line tool for generating a visual graph of your module dependencies and can be used to detect circular dependencies.
- Dependency Cruiser: NPM package that validates and visualizes dependencies.
- ESLint Plugin Import: While primarily used for linting imports, some ESLint configurations and plugins (eslint-plugin-import) can help detect circular dependencies.
- Custom Scripts: Depending on your project’s complexity, you might also write custom scripts to check for circular dependencies.
Here’s a basic example of a GitHub Actions workflow that detects circular dependencies using Madge:
name: Circular Dependency Check
on: [push, pull_request]
jobs:
build:
runs-on: ubuntu-latest
steps:
- uses: actions/checkout@v2
- name: Set up Node.js
uses: actions/setup-node@v1
with:
node-version: '18'
- name: Install dependencies
run: npm install
- name: Check for circular dependencies
run: npx madge --circular ./path/to/your/code
In this workflow, action triggers on every push and pull request. If a circular dependency is detected, the action can fail the build and send notifications to the developers. The typical response from developers should be to review the reported dependencies, refactor the code to break the cycle and push the changes back to the repository.
2. ESLint
ESLint is a widely used static code analysis tool in the JavaScript community. While it’s commonly used to enforce coding standards and identify syntax errors or anti-patterns, ESLint can also detect circular dependencies in JavaScript projects.
To use ESLint for detecting circular dependencies, you need to configure it appropriately. ESLint doesn’t have a built-in rule for detecting circular dependencies directly, but it can be combined with a plugin like eslint-plugin-import, which offers a rule no-cycle to detect import cycles. You can easily install this plugin through NPM:
npm i eslint-plugin-importOnce the plugin is installed, you need to configure your ESLint settings to use it. This is done in your project’s ESLint configuration file (.eslintrcor .eslintrc.js, .eslintrc.json depending on your setup). In the configuration file, you need to:
- Add the plugin: Include eslint-plugin-import in the list of plugins.
- Configure the no-cycle rule: This rule is specifically designed to detect circular dependencies.
{
"extends": ["eslint:recommended"],
"plugins": ["import"],
"rules": {
// other rules...
"import/no-cycle": [2, { "maxDepth": "∞" }]
},
// other configurations...
}
Here, the maxDepth option in the no-cycle rule determines how deep the plugin will look into your module imports to detect cycles. Since the maxDepth set to infinity ("∞"), ESLint will check for cycles at all depth levels of imports.
3. Bit
Bit is a next-generation build system for composable software. You can design, develop, build, test, and version a component in isolation in its own independent space. It’s particularly popular in front-end development but not limited to that. Here are some key aspects of Bit:
- Allows teams to share and collaborate on individual components of a project rather than the entire codebase.
- Just like Git manages source code versions, Bit manages versions of individual components. It keeps track of changes to components over time, making it easier to update and maintain them.
- Bit is designed to enable the development and testing of components in isolation. Each component can be worked on, tested, and deployed independently of the rest of the project.
- It provides a means for documenting components, making them easier to understand and use in their projects.
When it comes to circular dependency detection, Bit stands out as a prevention method rather than a detection method. Bit detects and prevents you from exporting code if there are any circular dependencies.
For example, let’s create 2 Bit components using Node.js:
After you’ve run the two commands, Bit will create two Node.js components using its default environment. Therefore, this will create a directory as shown below:
You’ll have your independent components created for you and you can start working on them, each in its own isolated space. Now, with Bit, it is able to intelligently build a dependency tree to understand that components that rely on each other.
So, let’s put this to the test and purposefully create a circular dependency by importing both components into one another.
Theroretically, Bit won’t let you export your components using the bit export command. Why?
Well, assume your components have a circular reference. Bit leverages Ripple CI to update components that have a diff in the tree. So, in a circular dependency, when one component updates, it’ll update its usages that’ll cause the first component to rebuild again. This creates an infinite build and can significantly eat up your build server resources!
So, Bit lets you avoid this out of the box via its command:
bit run insightsWith this command, you’re able to see a full picture of everything that’s wrong in your component. In fact, check out the diagrams shown below:
As you can see, you can get a greater understanding on the components that have a circular reference with each other to avoid cases of infinite builds.
So, if you’re working with Bit to build software, leverage bit insights to get insightful information on the state of your components.
Conclusion
This article discussed 3 simple yet powerful ways to spot and fix circular dependencies in JavaScript projects.
GitHub Actions helps catch these issues automatically when you push the code to GitHub, while ESLint finds and highlights any circular dependencies as you code. Bit stands out as a unique solution that prevents circular dependancies even before they start. These tools can make your coding life much easier and keep your projects running smoothly.
Thank you for reading.
