faasjs/faasjs

/**
 * Typescript transform based on [SWC](https://swc.rs/).
 *
 * [![License: MIT](https://img.shields.io/npm/l/@faasjs/ts-transform.svg)](https://github.com/faasjs/faasjs/blob/main/packages/faasjs/ts-transform/LICENSE)
 * [![NPM Version](https://img.shields.io/npm/v/@faasjs/ts-transform.svg)](https://www.npmjs.com/package/@faasjs/ts-transform)
 *
 * ## Install
 *
 * ```sh
 * npm install @faasjs/ts-transform
 * ```
 *
 * ## Usage
 *
 * ### Use as a register
 *
 * ```ts
 * import { addHook } from 'pirates'
 * import { transform } from '@faasjs/ts-transform'
 *
 * addHook((code, filename) => {
 *   if (filename.endsWith('.d.ts')) return ''
 *
 *   return transform(code, { filename }).code
 * }, {
 *   exts: [
 *     '.jsx',
 *     '.ts',
 *     '.tsx'
 *   ]
 * })
 * ```
 *
 * ### Use as a rollup plugin
 *
 * ```ts
 * import { Plugin, rollup } from 'rollup'
 * import { bundle } from '@faasjs/ts-transform'
 *
 * function tsTransform (): Plugin {
 *   return {
 *     name: 'tsTransform',
 *     async transform (code, filename) {
 *       return bundle({ filename })
 *     }
 *   }
 * }
 *
 * export default {
 *   input: 'index.ts',
 *   output: {
 *     dir: 'dist',
 *     format: 'es',
 *   },
 *   plugins: [
 *     tsTransform(),
 *   ],
 * }
 * ```
 * @packageDocumentation
 */
import {
  type JscConfig,
  type JscTarget,
  transformSync,
  bundle as swcBundle,
} from '@swc/core'
import { config } from '@swc/core/spack'
import { readFileSync } from 'node:fs'
import { join } from 'node:path'
import { deepMerge } from '@faasjs/deep_merge'

export const NodeBuiltinModules = [
  'async_hooks',
  'child_process',
  'cluster',
  'crypto',
  'dns',
  'events',
  'fs',
  'http',
  'http2',
  'https',
  'inspector',
  'net',
  'os',
  'path',
  'perf_hooks',
  'process',
  'querystring',
  'readline',
  'repl',
  'stream',
  'string_decoder',
  'tls',
  'trace_events',
  'tty',
  'dgram',
  'udp4',
  'url',
  'util',
  'v8',
  'vm',
  'wasi',
  'worker_threads',
  'zlib',
]

export function transform(
  code: string,
  options?: {
    /** default: process.cwd() */
    root?: string
    filename?: string
    /** default: `es2019` */
    target?: JscTarget
    /**
     * swc compilation
     * @see https://swc.rs/docs/configuration/compilation
     */
    jsc?: JscConfig
  }
) {
  if (!options) options = {}
  if (!options.root) options.root = process.cwd()
  if (!options.target) options.target = 'es2019'

  const tsconfig = JSON.parse(
    readFileSync(join(options.root, 'tsconfig.json')).toString()
  )

  if (!tsconfig.compilerOptions) tsconfig.compilerOptions = {}

  tsconfig.compilerOptions.baseUrl =
    tsconfig.compilerOptions.baseUrl?.replace('.', options.root) || options.root

  if (tsconfig.compilerOptions.paths) {
    for (const key of Object.keys(tsconfig.compilerOptions.paths))
      tsconfig.compilerOptions.paths[key] = tsconfig.compilerOptions.paths[
        key
      ].map((item: string) =>
        item.replace('.', tsconfig.compilerOptions.baseUrl)
      )
  } else tsconfig.compilerOptions.paths = {}

  return transformSync(code, {
    filename: options.filename,
    jsc: deepMerge(
      {
        parser: {
          syntax: 'typescript',
          tsx: true,
        },
        target: options.target,
        baseUrl: tsconfig.compilerOptions.baseUrl,
        paths: tsconfig.compilerOptions.paths,
        transform: { react: { runtime: 'automatic' } },
      },
      options.jsc
    ),
    module: { type: 'commonjs' },
  })
}

export async function bundle(options: {
  /** default: process.cwd() */
  root?: string
  filename: string
  /** default: `es2019` */
  jscTarget?: JscTarget
  /** has excluded node builtin modules */
  externalModules?: string[]
}) {
  if (!options.root) options.root = process.cwd()
  if (!options.jscTarget) options.jscTarget = 'es2019'

  const tsconfig = JSON.parse(
    readFileSync(join(options.root, 'tsconfig.json')).toString()
  )

  if (!tsconfig.compilerOptions) tsconfig.compilerOptions = {}

  tsconfig.compilerOptions.baseUrl =
    tsconfig.compilerOptions.baseUrl?.replace('.', options.root) || options.root

  if (tsconfig.compilerOptions.paths) {
    for (const key of Object.keys(tsconfig.compilerOptions.paths))
      tsconfig.compilerOptions.paths[key] = tsconfig.compilerOptions.paths[
        key
      ].map((item: string) =>
        item.replace('.', tsconfig.compilerOptions.baseUrl)
      )
  } else tsconfig.compilerOptions.paths = {}

  return swcBundle(
    config(
      deepMerge(
        {
          mode: 'production',
          entry: { index: options.filename },
          module: { type: 'commonjs' },
          options: {
            jsc: {
              parser: {
                syntax: 'typescript',
                tsx: true,
              },
              target: options.jscTarget,
              baseUrl: tsconfig.compilerOptions.baseUrl,
              paths: tsconfig.compilerOptions.paths,
              transform: { react: { runtime: 'automatic' } },
            },
          },
          externalModules: NodeBuiltinModules.concat(
            options.externalModules || []
          ),
        },
        options
      )
    )
  ).then(res => res.index)
}