Our Guide to Modern Front-End Build Pipelines

Published: Apr 23, 2024
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Overwhelmed by all of the tools available for the front-end build pipeline in your organization? Don't worry. We gathered all that we have learned about these tools while working on our projects and summarized it here. We collected all of the advice into a single place.

  • Andy LaiAndy Lai / Fullstack Engineer

Introduction

Modern web development has come a long way from the early days of manually writing HTML, CSS, and JavaScript in a simple text editor. The front-end ecosystem has grown exponentially, with many of tools, frameworks, and libraries now available to developers. As a result of the expansive choices available and the need for compatibility among them, deciding on which to include in your organization’s front-end build pipeline has become more complex than ever.

We’ll show you six ways you can modernize your front-end build pipeline to streamline development, improve performance, and ensure maintainable code in the long run. Most of all, these tools will allow you to build innovative features and create exceptional customer experiences that will inspire customers to return to your app and use it more often.

Implementing a JavaScript Framework or Library

Modern front-end development often relies on powerful JavaScript frameworks and libraries such as React, Angular, Vue. These frameworks simplify development, improve code quality, offer pre-built components, and provide support, making the development process more efficient, maintainable, and scalable.

  • Efficiency: Frameworks provide pre-built components and tools that make development faster and more efficient.
  • Code Reusability: Frameworks promote the reuse of code, allowing developers to use pre-built components and libraries, saving time and effort.
  • Best Practices: Frameworks come with established guidelines and coding conventions that improve code quality and maintainability.
  • Abstraction of Complexity: Frameworks handle complex tasks, such as browser compatibility and data management, so developers can focus on the core functionality.
  • Community Support: Frameworks have active communities that offer resources, knowledge-sharing, and support to developers.
  • Scalability and Maintainability: Frameworks provide features and patterns that support the growth and long-term maintenance of applications.
  • Security and Performance: Frameworks include security measures and performance optimizations to ensure robust and efficient applications.

Here's an overview of the pros and cons of each framework:

Angular
Pros:
  • Good performance and maintainability

  • Extensive tooling support (Angular-CLI)

  • Solid framework for large-scale projects

  • Built-in support for mobile app development (Ionic)

Cons:
  • Slower loading times due to regular DOM usage

  • Steeper learning curve

  • Limited support for unfamiliar or outdated browsers

ReactJS
Pros:
  • Efficient rendering with virtual DOM

  • Faster loading times

  • Logic and markup in one file

  • Easy to start and learn

  • Suitable for highly interactive web applications

Cons:
  • Not suitable for building MVC architecture alone

  • May require additional libraries for complex apps

  • Can be overwhelming with a large number of options and libraries available

VueJS
Pros:
  • Easy to use and integrate with other frameworks

  • Fast learning curve

  • Flexible and adaptable

  • Suitable for both small and large web applications

Cons:
  • Limited community support, especially in English-speaking regions

  • Certain areas of development can be overcomplicated due to excessive flexibility

How to choose one framework for your project:

  • Consider the Learning Curve: React has a straightforward learning curve, Vue is known for being beginner-friendly, and Angular has a steeper learning curve.

  • Evaluate Project Size and Complexity: React is suitable for projects of any size, Vue is versatile for different project sizes, and Angular is often preferred for larger, enterprise-level applications.

  • Assess the Community and Ecosystem: React has a large and active community, Vue has a growing community, and Angular has strong community support from Google.

  • Evaluate Performance: React and Vue offer efficient rendering, while Angular provides optimization for large applications.

  • Consider Flexibility and Customization: React offers high flexibility, Vue strikes a balance between flexibility and conventions, and Angular provides a comprehensive solution with built-in features.

  • Evaluate Tooling and Ecosystem: React has a wide range of libraries and tools, Vue has its official solutions, and Angular offers a complete set of tools.

  • Consider Community Feedback and Adoption: React and Vue are widely adopted, while Angular has a strong presence in enterprise-level projects.

  • Assess Long-term Maintenance and Support: React and Vue have active maintenance, while Angular is supported by Google and offers long-term support.

  • Consider Team Skills and Expertise: Leverage existing team skills if they have experience with a specific framework, or consider the learning curve and available resources for skill development.

Adopting a Module Bundler

Module bundlers such as Webpack, Parcel, and Rollup have become essential to modern front-end development. They allow you to bundle your project's assets (JavaScript, CSS, images, etc.) into efficient, optimized files for deployment.

Adopting a module bundler in your pipeline allows for:

  • Code Splitting: Break your code into smaller, more manageable chunks that can be loaded on-demand.

  • Tree Shaking: Eliminate dead code and unused dependencies from your final bundles.

  • Transpilation: Convert modern JavaScript syntax (ES6+) to widely supported ES5 syntax to ensure compatibility with older browsers.

  • Asset Optimization: Minify, compress, and optimize your assets to reduce file sizes and improve loading times.

Here's an overview of the pros and cons of each bundler:

Webpack
Pros:
  • Highly flexible and widely adopted bundler with a rich ecosystem

  • Extensive customization options and support for advanced features like code splitting and hot module replacement

  • Suitable for complex projects with diverse dependencies and module systems

Cons:
  • Steep learning curve and can be more configuration-heavy

  • Configuration setup can be complex, especially for beginners

  • Larger bundle sizes compared to other bundlers

Parcel
Pros:
  • Zero-configuration setup and easy to use

  • Provides a simple and intuitive developer experience

  • Automatic handling of bundling, minification, and hot module replacement

Cons:
  • Limited customization options and may require additional configuration for complex setups

  • Plugin ecosystem may not be as extensive as Webpack

  • Less suitable for large-scale or highly customized projects

Rollup
Pros:
  • Lightweight and efficient bundler, ideal for creating optimized bundles

  • Excellent at producing smaller bundle sizes

  • Effective tree shaking capabilities for removing unused code

Cons:
  • Requires more manual configuration and setup compared to other bundlers

  • Plugin ecosystem may not be as extensive as Webpack

  • Less suitable for projects with complex module systems or large dependency graphs

How to choose a bundler for your project:

  • Understand Your Needs: Identify what you want to achieve with a bundler, such as bundling and optimizing JavaScript, CSS, and assets.
  • Compare Features: Look at the main features offered by each bundler, such as code splitting, performance optimization, and ease of use. Choose the one that has the features you need.
  • Consider Configuration: Evaluate the complexity of configuration for each bundler. Choose one that is easy to set up and configure based on your team's expertise.
  • Check Community Support: Assess the size and activity of the communities surrounding each bundler. A larger community means more resources, support, and potential solutions to issues.
  • Assess Learning Curve: Consider the learning curve associated with each bundler. Choose one that aligns with your team's skill level and the time available for learning.
  • Integration with Other Tools: Consider how well each bundler integrates with other tools you are using in your project, such as CSS preprocessors or task runners.
  • Performance Considerations: Evaluate the performance optimizations provided by each bundler, such as code minification, compression, and asset loading. Choose one that meets your performance goals.
  • Tooling and Ecosystem: Consider the availability of plugins, loaders, and other tools that can enhance your development workflow. Choose a bundler with a supportive ecosystem.
  • Future Maintenance: Choose a bundler that is actively maintained and has a roadmap for future improvements. This ensures ongoing support and compatibility with future technologies.

Here's an example of how you can configure Webpack:

  1. Install Webpack and required plugins

    npm install webpack webpack-cli --save-dev
    
  2. Create a Webpack configuration file (e.g., webpack.config.js) in the root of your project:

    const path = require('path');
    
    module.exports = {
      entry: './src/index.js', // Entry point of your application
      output: {
        path: path.resolve(__dirname, 'dist'), // Output directory
        filename: 'bundle.js', // Output file name
      },
      module: {
        rules: [
          {
            test: /\.js$/, // Apply loaders to JavaScript files
            exclude: /node_modules/,
            use: {
              loader: 'babel-loader', // Example: Use Babel to transpile JavaScript
              options: {
                presets: ['@babel/preset-env'],
              },
            },
          },
          // Add more rules for different file types (e.g., CSS, images, etc.)
        ],
      },
      // Add plugins and other configuration options as needed
    };
    
  3. Customize the configuration to fit your project's needs

  4. Create a script in your package.json file to run Webpack:

    {
        "scripts": {
            "build": "webpack --config webpack.config.js"
        }
    }
    
  5. Run Webpack using the configured script:

    npm run build
    

Embracing a CSS Preprocessor

CSS preprocessors such as Sass, Less, and Stylus provide powerful features that extend the capabilities of plain CSS. CSS preprocessors helps streamline the development process, reduces code duplication, promotes consistency, and enhances code organization, they allow you to write cleaner, more maintainable CSS code by adding:

  • Variables: Store reusable values such as colors, fonts, and sizes
  • Nesting: Write nested CSS rules to better reflect the structure of your HTML
  • Mixins: Create reusable chunks of CSS code that can be included in other stylesheets
  • Functions: Perform calculations and manipulate values in your stylesheets, it allows you to create versatile styles that adapt to different situations. For example, you can define a function that generates different font sizes based on screen sizes

Here's an overview of the pros and cons of each CSS preprocessor:

Sass
Pros:
  • Mature and widely adopted CSS preprocessor

  • Offers a rich set of features, including variables, mixins, nesting, and inheritance, which enhance productivity and code maintainability

  • Large community support and extensive documentation

  • Can be easily integrated into existing projects

Cons:
  • Requires a build step to compile Sass code into CSS, which adds complexity to the development process

  • Learning curve, especially for beginners not familiar with CSS preprocessors

Less
Pros:
  • Easy to learn and use, especially for developers already familiar with CSS

  • Offers a similar set of features as Sass, such as variables, mixins, and nested rules

  • Supports both traditional CSS syntax and Less-specific syntax

  • Good browser compatibility and can be used with minimal configuration

Cons:
  • Smaller community compared to Sass, resulting in a comparatively smaller ecosystem of community-created tools and resources

  • Limited support for advanced features like built-in functions and control directives

  • Less tooling and integration options compared to Sass

Stylus
Pros:
  • Concise and expressive syntax, with a focus on simplicity and readability

  • Powerful features like variables, mixins, and nested selectors

  • Extensive flexibility and customization options

  • Supports both CSS-like syntax and indented syntax

Cons:
  • Smaller community compared to Sass and Less, which may result in fewer resources and community-generated tools

  • Learning curve, especially for developers not familiar with Stylus or CSS preprocessors in general

  • Limited tooling and integration options compared to Sass

How to choose a CSS preprocessor for your project:

  • Identify Project Needs: Understand what you want to achieve with a preprocessor, such as code organization, reusability, or improved productivity.
  • Compare Features: Look at the main features offered by each preprocessor, such as variables, mixins, nesting, and inheritance. Choose the one that has the features you need.
  • Consider Ease of Use: Evaluate the learning curve and ease of adoption for each preprocessor. Choose the one that you and your team find the most user-friendly and intuitive.
  • Check Community Support: Assess the size and activity of the communities surrounding each preprocessor. A larger community means more resources, support, and potential solutions to problems.
  • Evaluate Integration: Consider the compatibility of each preprocessor with your existing tools, build systems, and editors. Choose one that integrates smoothly into your development workflow.
  • Assess Long-Term Viability: Look for preprocessor options that are actively maintained and have a roadmap for future improvements. This ensures ongoing support and enhancements.nts. This ensures ongoing support and compatibility with future technologies.

Here's an example of how you can configure Sass in a Webpack project:

  1. Install required dependencies

    npm install sass sass-loader css-loader style-loader --save-dev
    
  2. Update your Webpack configuration file (webpack.config.js) to add the necessary loaders

    module.exports = {
      // ...other configuration options
      module: {
        rules: [
          // ...other rules
          {
            test: /\.s[ac]ss$/i, // Match .scss or .sass files
            use: [
              'style-loader', // Injects styles into the DOM
              'css-loader', // Translates CSS into CommonJS
              'sass-loader', // Compiles Sass to CSS
            ],
          },
        ],
      },
    };
    
  3. Create a Sass file (e.g., styles.scss) and import it in your JavaScript entry file (e.g., index.js)

    // styles.scss
    body {
      background-color: #f1f1f1;
    }
    
    // index.js
    import './styles.scss';
    
  4. Build and run your Webpack project

    npm run build
    

Utilizing Linters and Formatters

Linters and formatters such as ESLint, Prettier, and Stylelint help enforce consistent coding styles and catch potential errors before they become problems. Spend your team’s time during code reviews reviewing code and approaches, not formatting issues. And spend less time QA-ing issues related to tiny bugs that could have been avoided. Integrating these tools into your build pipeline can:

  • Improve Code Quality: Automatically catch syntax errors, potential bugs, and performance issues.
  • Enforce Coding Standards: Ensure a consistent coding style across your team, making the codebase easier to read and maintain.
  • Streamline Code Reviews: Reduce the time spent on nitpicking code formatting during code reviews by automating the process.
  • Avoid Tiny Bugs: Without linters, you might overlook common syntax errors and Unused Variables or Parameters.

To make the most of these tools, set up pre-commit hooks that automatically lint and format your code before each commit, here's an example of how you can configure it:

  1. Install the required packages

    npm install husky lint-staged eslint prettier --save-dev
    
  2. Configure ESLint: Create an ESLint configuration file (e.g., .eslintrc.js) in the root of your project and specify your desired rules and configurations. For example:

    module.exports = {
      // ESLint rules and configurations
      // ...
    };
    
  3. Configure Prettier: Create a Prettier configuration file (e.g., .prettierrc.js) in the root of your project and specify your desired formatting rules. For example:

    module.exports = {
      // Prettier formatting rules
      // ...
    };
    
  4. Configure Husky and lint-staged: In your package.json file, add the following configuration:

    {
       "husky": {
         "hooks": {
           "pre-commit": "lint-staged"
         }
       },
       "lint-staged": {
         "*.{js,jsx,ts,tsx}": ["eslint --fix", "prettier --write", "git add"]
       }
    }
    

    This configuration sets up a pre-commit hook using Husky that triggers lint-staged, which in turn runs ESLint with the --fix flag to automatically fix linting issues and Prettier to format the code. Finally, it stages the modified files using git add.

  5. Run the pre-commit hook: Now, whenever you make a commit, the pre-commit hook will automatically run ESLint and Prettier on the staged files. If there are any linting errors or formatting inconsistencies, it will attempt to fix them before the commit is made.

Running tests

Running tests is a crucial aspect of JavaScript project development to ensure code quality and reliability. This brief guide will cover two important types of tests: unit tests and end-to-end testing.

Unit Tests

Unit tests focus on testing individual units or components of your code in isolation. Here's a brief overview:

  • Purpose: Verify the correctness of small, independent units of code.
  • Scope: Each test targets a specific function, module, or component.
  • Dependencies: External dependencies are often mocked or stubbed to isolate the unit being tested.
  • Tooling: Popular unit testing frameworks for JavaScript include Jest, Mocha, and Jasmine
Jest
Pros:
  • All-in-one Solution: Jest comes bundled with everything you need for testing, including test runners, assertions, mocking, and code coverage

  • Easy Setup: Jest is known for its simple and straightforward setup process, making it beginner-friendly

  • Snapshot Testing: Jest offers a convenient snapshot testing feature for comparing test output with saved snapshots

  • Parallel Execution: Jest can run tests in parallel, making it faster for large test suites

  • Strong Community: Jest has a large and active community, providing extensive support and resources

Cons:
  • Learning Curve: Jest may have a learning curve, especially when configuring complex setups or advanced features

  • Opinionated: Jest follows its own conventions, which may not integrate smoothly with existing projects or preferences

Mocha
Pros:
  • Flexibility: Mocha is highly flexible and allows you to choose your preferred assertion library, mocking framework, and other tools

  • Large Ecosystem: Mocha has a vast ecosystem with a wide range of plugins and integrations

  • Async Testing: Mocha has excellent support for testing asynchronous code

  • Simple Syntax: Mocha's syntax is clean and easy to read, making it accessible for developers

Cons:
  • Configuration Required: Mocha requires additional configuration to set up assertions, mocking, and other testing tools

  • Minimalist Approach: Mocha's simplicity can sometimes result in a lack of built-in features, requiring additional libraries for certain functionalities

Jasmine
Pros:
  • Easy to Get Started: Jasmine has a simple and intuitive syntax, making it beginner-friendly

  • Self-Contained: Jasmine provides everything you need for testing in a single package, reducing the need for additional dependencies

  • Readable Tests: Jasmine's syntax is designed to create readable and descriptive tests

  • Built-in Mocking: Jasmine has built-in support for mocking and spies, making it easy to test dependencies

Cons:
  • Limited Ecosystem: Jasmine's ecosystem is smaller compared to Jest and Mocha, resulting in fewer plugins and integrations

  • Slower Execution: Jasmine can be slower than other frameworks when running large test suites

  • Opinionated Syntax: Jasmine's syntax may not align with personal preferences or existing project standards

End-to-End Testing

End-to-end (E2E) testing simulates real user scenarios by testing the entire application flow. Here's a brief overview:

  • Purpose: Validate the behavior and functionality of the entire application from start to finish.
  • Scope: Tests cover multiple components, interactions, and external dependencies.
  • Dependencies: Real or simulated dependencies are used to mirror the actual environment.
  • Tooling: Frameworks like Playwright, Cypress, Puppeteer, and are commonly used for E2E testing.
Playwright
Pros:
  • Cross-browser Support: Playwright allows you to test your applications across different browsers like Chrome, Firefox, and Safari

  • Multi-page and Multi-context Support: Playwright can handle multiple pages and contexts within a single browser instance, making it suitable for complex testing scenarios

  • Powerful Automation API: Playwright offers a robust automation API with features like intercepting network requests and emulating mobile devices

  • Speed and Reliability: Playwright is known for its fast test execution and reliable results, reducing flakiness in tests

  • Active Community: Playwright has a growing community, providing support and regular updates

Cons:
  • Learning Curve: Playwright may have a learning curve due to its comprehensive functionality and advanced features

Cypress
Pros:
  • Easy Setup: Cypress has a simple setup process, allowing you to get started quickly

  • Built-in Features: Cypress includes built-in features like time-travel debugging, automatic waiting, and real-time reloading

  • Interactive Test Execution: Cypress provides an interactive test runner that allows you to see the application state during test execution

  • Comprehensive Documentation: Cypress offers extensive documentation and an active community for support

  • Excellent Developer Experience: Cypress focuses on providing a seamless testing experience with a user-friendly interface

Cons:
  • Limited Browser Support: Cypress primarily supports modern browsers and has limited cross-browser testing capabilities

  • Single Tab Limitation: Cypress only supports testing within a single browser tab, which may be limiting for certain scenarios

Puppeteer
Pros:
  • Headless Chrome Automation: Puppeteer is built on top of the Chrome DevTools Protocol, offering powerful Chrome automation capabilities

  • Versatile Web Scraping: Puppeteer is widely used for web scraping tasks due to its ability to navigate and interact with web pages

  • Extensive API: Puppeteer provides a comprehensive API for controlling Chrome and handling various web automation tasks

  • Active Development: Puppeteer is actively maintained by the Google Chrome team and receives regular updates

Cons:
  • Limited to Chrome: Puppeteer only supports Chrome and does not have built-in cross-browser testing capabilities

  • Lower-level API: Puppeteer's API is more low-level compared to other frameworks, requiring more code for common testing scenarios

  • Steeper Learning Curve: Using Puppeteer effectively may require a deeper understanding of Chrome's DevTools Protocol

Leveraging Continuous Integration (CI) and Continuous Deployment (CD)

Continuous Integration (CI) and Continuous Deployment (CD) are practices that involve automatically building, testing, and deploying your code whenever changes are made. By incorporating CI/CD into your build pipeline, you can:

  • Catch errors early: Automatically run tests and linters on every commit, alerting you to potential issues before they reach production.
  • Code Quality Analysis: SonarQube performs static code analysis to identify code smells, bugs, vulnerabilities, and other quality issues. It analyzes your codebase against a set of predefined rules and provides detailed reports highlighting areas that need improvement. By integrating SonarQube into your CI/CD pipeline, you can catch code issues early and ensure that your codebase adheres to best practices and industry standards.
  • Automate deployments: Automatically deploy your code to staging or production environments, reducing the risk of human error.
  • Streamline collaboration: Ensure that all team members are working with the latest, error-free code at all times.

Popular CI/CD platforms include GitHub Actions, GitLab CI/CD, and CircleCI.

GitHub Actions
Pros:
  • Tight integration with GitHub

  • Easy to get started

  • Scalable

  • Cost-effective for open-source projects

Cons:
  • Limited support for self-hosted runners

  • Complexity for complex workflows

GitLab CI/CD
Pros:
  • Comprehensive DevOps platform

  • Powerful pipeline configuration

  • Support for self-hosted runners

Cons:
  • Learning curve

  • Limited marketplace for pre-built actions

CircleCI
Pros:
  • Ease of use

  • Fast and efficient builds

  • Extensive integration ecosystem

Cons:
  • Limited free tier

  • Limited visibility into intermediate pipeline stages

To give you an idea of how a CI/CD platform could work for your team, let’s explore how you could use GitHub Actions.

Start by configuring a GitHub Actions workflow to be triggered when an event occurs in your repository, such as a pull request being opened or updated. Your workflow may contain one or more jobs which can run in sequential order or in parallel.

Here's an example of a GitHub Actions workflow:

  1. Check whether the PR contains relevant descriptions.
  2. Step environment, such as installing node, dependencies, pulling code, etc.
  3. Run unit tests and linters.
  4. Run end-to-end test in parallel.
  5. Run code analysis.
  6. Run lighthouse test.
  7. Deploy the code to CDN.

screenshot-deploy-the-code-to-cdn.png

To use GitHub Actions in your project, follow these steps:

  1. Set up a GitHub repository: Create a new GitHub repository or navigate to an existing repository where you want to use GitHub Actions.
  2. Define your workflow: Inside your repository, create a new directory called .github/workflows. This is where you'll define your workflow configuration files.
  3. Create a workflow file: Inside the .github/workflows directory, create a new YAML file (e.g., main.yml) to define your workflow's configuration. This file will contain the steps and actions that make up your workflow.
  4. Define the workflow configuration: In the workflow file, you'll define the events that trigger the workflow and the jobs that need to be executed. You can use predefined actions, run custom scripts, or use a combination of both. Here's a simple example that runs tests on every push to the main branch:
name: CI

on:
  push:
    branches:
      - main

jobs:
  build:
    runs-on: ubuntu-latest

    steps:
      - uses: actions/checkout@v2

      - name: Install dependencies
        run: npm ci

      - name: Run tests
        run: npm test
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