Optimizing Builds with esbuild

Optimizing Builds with esbuild

One of the key advantages of using esbuild is its speed, but there are several ways to further optimize your builds to achieve better performance and more efficient output. In this section, we will cover techniques such as incremental builds, caching, parallelization, and multi-threading, as well as other best practices for optimizing your esbuild setup.

1. Performance Considerations

When building large applications, performance can be impacted by the size of your codebase, the complexity of your build process, and the efficiency of the tools you use. Here are some general tips to keep in mind:

• Minimize the number of entry points: Reducing the number of entry points can decrease the amount of work esbuild needs to do, resulting in faster builds.
• Avoid unnecessary plugins: While plugins can extend esbuild’s functionality, they can also slow down the build process. Use only the plugins you truly need.
• Use the target option: By specifying a target environment (e.g., es2020, chrome90), you can limit the amount of polyfilling and transformations esbuild needs to perform, resulting in faster and smaller builds.

2. Incremental Builds and Caching

Incremental builds allow esbuild to reuse previous work when files haven’t changed, which can significantly speed up the build process during development.

Example: Enabling incremental builds

You can enable incremental builds in your esbuild configuration:

	// build.js
	
	const esbuild = require('esbuild');
	
	esbuild
	  .build({
	    entryPoints: ['src/app.js'],
	    bundle: true,
	    outfile: 'dist/bundle.js',
	    incremental: true // Enable incremental builds
	  })
	  .then((result) => {
	    // Store the result for future builds
	    let buildResult = result;
	
	    // Use buildResult.rebuild() for subsequent builds
	    buildResult.rebuild();
	  })
	  .catch(() => process.exit(1));

With incremental builds enabled, esbuild can reuse information from previous builds, speeding up subsequent builds.

Caching:

Caching can further improve build performance by storing and reusing compiled modules between builds. While esbuild does not have built-in caching, you can integrate it with external caching solutions like babel-loader or webpack if needed.

3. Parallelization and Multi-Threading

esbuild is designed to take full advantage of modern multi-core processors, automatically parallelizing tasks and utilizing multiple threads to speed up the build process.

Example: Multi-threading is enabled by default

You don’t need to do anything special to enable parallelization and multi-threading in esbuild—it’s built into the tool. esbuild will automatically split tasks across multiple CPU cores to optimize build performance.

Example: Reducing the number of threads (if needed)

If, for any reason, you need to limit the number of threads esbuild uses (e.g., to reduce CPU usage on a shared system), you can do so using the ESBUILD_MAX_THREADS environment variable:

	ESBUILD_MAX_THREADS=4 npx esbuild src/app.js --bundle --outfile=dist/bundle.js

4. Other Optimization Techniques

There are several other techniques you can use to optimize your esbuild setup:

• Tree Shaking: Ensure that tree shaking is enabled to remove unused code and reduce bundle size. esbuild performs tree shaking automatically during the bundling process.
• Code Splitting: Use dynamic import() statements to split your code into smaller chunks that can be loaded on demand. This is particularly useful for large applications where not all code is needed upfront.
• Minification: Always enable minification for production builds to reduce the size of your output files.
• Target Modern Browsers: By targeting modern browsers, you can reduce the amount of polyfilling and code transpilation required, leading to faster builds and smaller bundles.

Example: Optimizing for modern browsers

	// build.js
	
	const esbuild = require('esbuild');
	
	esbuild
	  .build({
	    entryPoints: ['src/app.js'],
	    bundle: true,
	    minify: true, // Minify the output
	    target: ['es2020', 'chrome90'], // Target modern browsers
	    outfile: 'dist/bundle.js'
	  })
	  .catch(() => process.exit(1));