gulp-esbuild/index.js

gulp plugin for esbuild bundler

const {Transform} = require('stream')
const {build, context} = require('esbuild')
const PluginError = require('plugin-error')
const Vinyl = require('vinyl')
const {name: PLUGIN_NAME} = require('./package.json')
const resolvePlugin = require('./resolve-plugin')
const metaFileDefaultName = 'metafile.json'

//
// helpers
//

function createFile(file) {
	return new Vinyl(file)
}

function createError(err) {
	return new PluginError(PLUGIN_NAME, err, {showProperties: false})
}

function createTransformStream(flushFn, entryPoints) {
	return new Transform({
		objectMode: true,
		transform(file, _, cb) {
			if (!file.isBuffer()) {
				return cb(createError(new TypeError('File should be a buffer')))
			}

			entryPoints.push(file)
			cb(null)
		},
		flush: flushFn,
	})
}

function splitOptions(options) {
	const {metafileName, ...esbuildOptions} = options
	return {metafileName, esbuildOptions}
}

//
// handlers
//

function createGulpEsbuild({incremental} = {}) {
	if (incremental) {
		return incrementalBuild()
	}

	return simpleBuild()
}

function simpleBuild() {
	return function plugin(pluginOptions = {}) {
		/** @type Array<import('vinyl').BufferFile> */
		const entryPoints = []
		const {metafileName, esbuildOptions} = splitOptions(pluginOptions)

		async function flushFunction(cb) {
			const params = {
				logLevel: 'silent',
				...esbuildOptions,
				entryPoints: entryPoints.map(entry => entry.path),
				write: false,
				plugins: [
					resolvePlugin(entryPoints),
					...(esbuildOptions.plugins || []),
				],
			}

			// set outdir by default
			if (!esbuildOptions.outdir && !esbuildOptions.outfile) {
				params.outdir = '.'
			}

			let result

			try {
				result = await build(params)
			} catch(err) {
				return cb(createError(err))
			}

			result.outputFiles.forEach(file => {
				this.push(createFile({
					path: file.path,
					contents: Buffer.from(file.contents),
				}))
			})

			if (result.metafile) {
				const name = metafileName || metaFileDefaultName

				this.push(createFile({
					path: name,
					contents: Buffer.from(JSON.stringify(result.metafile)),
				}))
			}

			cb(null)
		}

		return createTransformStream(flushFunction, entryPoints)
	}
}

function incrementalBuild() {
	let ctx

	return function plugin(pluginOptions = {}) {
		/** @type Array<import('vinyl').BufferFile> */
		const entryPoints = []
		const {metafileName, esbuildOptions} = splitOptions(pluginOptions)

		async function flushFunction(cb) {
			const params = {
				logLevel: 'silent',
				...esbuildOptions,
				entryPoints: entryPoints.map(entry => entry.path),
				write: false,
				plugins: [
					resolvePlugin(entryPoints),
					...(esbuildOptions.plugins || []),
				],
			}

			// set outdir by default
			if (!esbuildOptions.outdir && !esbuildOptions.outfile) {
				params.outdir = '.'
			}

			let result

			try {
				// if it's the first build
				if (!ctx) {
					ctx = await context(params)
				}
				
				result = await ctx.rebuild()
			} catch(err) {
				return cb(createError(err))
			}

			result.outputFiles.forEach(file => {
				this.push(createFile({
					path: file.path,
					contents: Buffer.from(file.contents),
				}))
			})

			if (result.metafile) {
				const name = metafileName || metaFileDefaultName

				this.push(createFile({
					path: name,
					contents: Buffer.from(JSON.stringify(result.metafile)),
				}))
			}

			cb(null)
		}

		return createTransformStream(flushFunction, entryPoints)
	}
}

module.exports = createGulpEsbuild()
module.exports.createGulpEsbuild = createGulpEsbuild