@samual/rolldown-config/default.js

My Rolldown config

import { parseAsync, traverse } from "@babel/core"
import babelPluginSyntaxTypescript from "@babel/plugin-syntax-typescript"
import babelPresetEnv from "@babel/preset-env"
import babelPresetTypescript from "@babel/preset-typescript"
import { babel } from "@rollup/plugin-babel"
import terser from "@rollup/plugin-terser"
import { expect } from "@samual/assert"
import { babelPluginHere } from "babel-plugin-here"
import { babelPluginVitest } from "babel-plugin-vitest"
import { defu } from "defu"
import { readdir } from "fs/promises"
import { cpus } from "os"
import * as Path from "path"
import prettier from "rollup-plugin-prettier"
const rolldownConfig = async ({
	sourcePath = "src",
	rolldownOptions,
	babelOptions,
	terserOptions,
	prettierOptions,
	experimental
} = {}) =>
	defu(rolldownOptions, {
		external: source => !(Path.isAbsolute(source) || source.startsWith(".")),
		input: Object.fromEntries(
			(await readdir(sourcePath, { withFileTypes: !0, recursive: !0 }))
				.filter(dirent => dirent.isFile())
				.map(dirent => Path.join((dirent => dirent.parentPath ?? dirent.path)(dirent), dirent.name))
				.filter(
					path =>
						(path.endsWith(".js") && !path.endsWith(".test.js")) ||
						(path.endsWith(".ts") && !path.endsWith(".d.ts") && !path.endsWith(".test.ts"))
				)
				.map(path => [path.slice(sourcePath.length + 1, -3), path])
		),
		output: { dir: "dist" },
		plugins: [
			babel(
				defu(babelOptions, {
					babelHelpers: "bundled",
					extensions: [".ts"],
					presets: [
						[babelPresetEnv, { targets: { node: "20.10" } }],
						[babelPresetTypescript, { allowDeclareFields: !0, optimizeConstEnums: !0 }]
					],
					plugins: [babelPluginHere(), babelPluginVitest()]
				})
			),
			terser(
				defu(terserOptions, {
					compress: { passes: Infinity, unsafe: !0, sequences: !1, keep_infinity: !0 },
					maxWorkers: Math.floor(cpus().length / 2),
					mangle: !1,
					ecma: 2020
				})
			),
			experimental?.noSideEffects && {
				name: "no-side-effects",
				async renderChunk(code) {
					const ast = expect(await parseAsync(code, { plugins: [babelPluginSyntaxTypescript] })),
						indexes = []
					traverse(ast, {
						Function(path) {
							!path.node.loc ||
								path.node.type.endsWith("Method") ||
								(path.isExpression() && "VariableDeclarator" != path.parentPath.node.type) ||
								!path.isPure() ||
								indexes.push(path.node.loc.start.index)
						}
					})
					indexes.sort((a, b) => b - a)
					for (const index of indexes)
						code = `${code.slice(0, index)}/*@__NO_SIDE_EFFECTS__*/${code.slice(index)}`
					return code
				}
			},
			experimental?.disablePrettier
				? void 0
				: prettier(
						defu(prettierOptions, {
							parser: "espree",
							useTabs: !0,
							tabWidth: 4,
							arrowParens: "avoid",
							printWidth: 120,
							semi: !1,
							trailingComma: "none"
						})
					)
		],
		preserveEntrySignatures: "strict",
		treeshake: { moduleSideEffects: !1 }
	})
export { rolldownConfig }