esbuild-plugin-ts-decorators

esbuild-plugin-ts-decorators

This is a plugin for esbuild to handle the tsconfig setting "emitDecoratorMetadata": true. When the decorator flag is set to true, the build process will inspect each .ts file and upon a decorator, will transpile with TypeScript.

In watch mode this plugin will cache those files by default, and rebuild them with TypeScript only if there are changes.

Usage

Install esbuild and the plugin

npm install -D esbuild
npm install -D esbuild-plugin-ts-decorators

Set up a build script

import { build } from 'esbuild';
import { esbuildDecorators } from 'esbuild-plugin-ts-decorators';

async function myBuilder(
	tsconfig: string,
	entryPoints: string[],
	outfile: string,
	cwd: string = process.cwd()
) {
	const buildResult = await build({
		platform: 'node',
		target: 'node14',
		bundle: true,
		sourcemap: 'external',
		plugins: [
			esbuildDecorators({
				tsconfig,
				cwd,
				cache: true,
			}),
		],
		watch: true,
		tsconfig,
		entryPoints,
		outfile,
		external: [
			// This is likely to be your friend...
		],
	});
}

Run your builder.

Options

Option	Description
tsconfig	optional : string : The path and filename of the tsconfig.json.
cwd	optional : string : The current working directory.
tsx	optional : boolean : Enable .tsx file support. Default is false.
force	optional : boolean : Will transpile decorators with TypeScript even if emitDecoratorMetadata is false.
cache	optional : boolean : Whether to cache TypeScript builds in memory. Defaults to true when in watch mode.
cacheSize	optional : number : Maximum size of the cache in MB. Defaults to 128 MB.

Caveats

There is no doubt that this will affect the performance of esbuild. When emitDecoratorMetadata is set, every file will have to be loaded into this plugin.

This simple plugin hangs on the regex string: /((?<![(\s]\s*['"])@\w[.[\]\w\d]*\s*(?![;])[((?=\s)])/

Potentially esbuild could eventually do this regex search and expose positives via another plugin hook for transpiling.

Issue here: https://github.com/evanw/esbuild/issues/991

Decorator Match Testing

Check out the test files and submit any issues or PRs if you see a pattern that should be covered.

Credits

Thanks to Thomas Schaaf and Brian McBride as this plugin is based on their code. Original Source

Thanks to the npm package strip-comments that was stripped down to cover only typescript comments and string removals