swc transpiler and new --transpiler option to use third-party transpilers

package.json

@@ -23,6 +23,7 @@
     "./esm.mjs": "./esm.mjs",
     "./esm/transpile-only": "./esm/transpile-only.mjs",
     "./esm/transpile-only.mjs": "./esm/transpile-only.mjs",
+    "./transpilers/swc-experimental": "./transpilers/swc-experimental.js",
     "./node10/tsconfig.json": "./node10/tsconfig.json",
     "./node12/tsconfig.json": "./node12/tsconfig.json",
     "./node14/tsconfig.json": "./node14/tsconfig.json"
@@ -36,6 +37,7 @@
     "ts-node-transpile-only": "dist/bin-transpile.js"
   },
   "files": [
+    "transpilers/",
     "dist/",
     "dist-raw/",
     "register/",
@@ -105,6 +107,8 @@
     "timeout": "300s"
   },
   "devDependencies": {
+    "@swc/core": ">=1.2.45",
+    "@swc/wasm": ">=1.2.45",
     "@types/chai": "^4.0.4",
     "@types/diff": "^4.0.2",
     "@types/lodash": "^4.14.151",
@@ -134,8 +138,18 @@
     "util.promisify": "^1.0.1"
   },
   "peerDependencies": {
+    "@swc/core": ">=1.2.45",
+    "@swc/wasm": ">=1.2.45",
     "typescript": ">=2.7"
   },
+  "peerDependenciesMeta": {
+    "@swc/core": {
+      "optional": true
+    },
+    "@swc/wasm": {
+      "optional": true
+    }
+  },
   "dependencies": {
     "@tsconfig/node10": "^1.0.7",
     "@tsconfig/node12": "^1.0.7",

src/bin.ts

@@ -41,6 +41,7 @@ export function main (argv: string[] = process.argv.slice(2), entrypointArgs: Re
       '--ignore-diagnostics': [String],
       '--ignore': [String],
       '--transpile-only': Boolean,
+      '--transpiler': String,
       '--type-check': Boolean,
       '--compiler-host': Boolean,
       '--pretty': Boolean,
@@ -95,6 +96,7 @@ export function main (argv: string[] = process.argv.slice(2), entrypointArgs: Re
     '--ignore': ignore,
     '--transpile-only': transpileOnly,
     '--type-check': typeCheck,
+    '--transpiler': transpiler,
     '--compiler-host': compilerHost,
     '--pretty': pretty,
     '--skip-project': skipProject,
@@ -120,11 +122,12 @@ export function main (argv: string[] = process.argv.slice(2), entrypointArgs: Re
     --cwd-mode                     Use current directory instead of <script.ts> for config resolution
     --show-config                  Print resolved configuration and exit
 
-    -T, --transpile-only           Use TypeScript's faster \`transpileModule\`
+    -T, --transpile-only           Use TypeScript's faster \`transpileModule\` or a third-party transpiler
     -H, --compiler-host            Use TypeScript's compiler host API
     -I, --ignore [pattern]         Override the path patterns to skip compilation
     -P, --project [path]           Path to TypeScript JSON project file
     -C, --compiler [name]          Specify a custom TypeScript compiler
+    --transpiler [name]            Specify a third-party, non-typechecking transpiler
     -D, --ignore-diagnostics [code] Ignore TypeScript warnings by diagnostic code
     -O, --compiler-options [opts]   JSON object to merge with compiler options
 
@@ -159,8 +162,9 @@ export function main (argv: string[] = process.argv.slice(2), entrypointArgs: Re
     emit,
     files,
     pretty,
-    transpileOnly,
+    transpileOnly: transpileOnly ?? transpiler != null ? true : undefined, // tslint:disable-line:strict-type-predicates
     typeCheck,
+    transpiler,
     compilerHost,
     ignore,
     preferTsExts,

src/index.spec.ts

@@ -99,6 +99,8 @@ test.suite('ts-node', (test) => {
     testsDirRequire.resolve('ts-node/esm/transpile-only')
     testsDirRequire.resolve('ts-node/esm/transpile-only.mjs')
 
+    testsDirRequire.resolve('ts-node/transpilers/swc-experimental')
+
     testsDirRequire.resolve('ts-node/node10/tsconfig.json')
     testsDirRequire.resolve('ts-node/node12/tsconfig.json')
     testsDirRequire.resolve('ts-node/node14/tsconfig.json')
@@ -272,6 +274,18 @@ test.suite('ts-node', (test) => {
       expect(err.message).to.contain('error TS1003: Identifier expected')
     })
 
+    test('should support third-party transpilers via --transpiler', async () => {
+      const { err, stdout } = await exec(`${cmdNoProject} --transpiler ts-node/transpilers/swc-experimental transpile-only-swc`)
+      expect(err).to.equal(null)
+      expect(stdout).to.contain('hello world')
+    })
+
+    test('should support third-party transpilers via tsconfig', async () => {
+      const { err, stdout } = await exec(`${cmdNoProject} transpile-only-swc-via-tsconfig`)
+      expect(err).to.equal(null)
+      expect(stdout).to.contain('hello world')
+    })
+
     test('should pipe into `ts-node` and evaluate', async () => {
       const execPromise = exec(cmd)
       execPromise.child.stdin!.end("console.log('hello')")

src/index.ts

@@ -7,6 +7,7 @@ import { fileURLToPath } from 'url'
 import type * as _ts from 'typescript'
 import { Module, createRequire as nodeCreateRequire, createRequireFromPath as nodeCreateRequireFromPath } from 'module'
 import type _createRequire from 'create-require'
+import { Transpiler, TranspilerFactory } from './transpilers/types'
 import { getDefaultTsconfigJsonForNodeVersion } from './tsconfigs'
 
 /** @internal */
@@ -132,6 +133,19 @@ export interface TSCommon {
   parseJsonConfigFileContent: typeof _ts.parseJsonConfigFileContent
   formatDiagnostics: typeof _ts.formatDiagnostics
   formatDiagnosticsWithColorAndContext: typeof _ts.formatDiagnosticsWithColorAndContext
+
+  createDocumentRegistry: typeof _ts.createDocumentRegistry
+  JsxEmit: typeof _ts.JsxEmit
+  createModuleResolutionCache: typeof _ts.createModuleResolutionCache
+  resolveModuleName: typeof _ts.resolveModuleName
+  resolveModuleNameFromCache: typeof _ts.resolveModuleNameFromCache
+  resolveTypeReferenceDirective: typeof _ts.resolveTypeReferenceDirective
+  createIncrementalCompilerHost: typeof _ts.createIncrementalCompilerHost
+  createSourceFile: typeof _ts.createSourceFile
+  getDefaultLibFileName: typeof _ts.getDefaultLibFileName
+  createIncrementalProgram: typeof _ts.createIncrementalProgram
+  createEmitAndSemanticDiagnosticsBuilderProgram: typeof _ts.createEmitAndSemanticDiagnosticsBuilderProgram
+
   libs?: string[]
 }
 
@@ -156,6 +170,10 @@ export namespace TSInternal {
   }
 }
 
+export interface TSCompilerFactory {
+  createTypescriptCompiler (options?: any): TSCommon
+}
+
 /**
  * Export the current version.
  */
@@ -237,6 +255,10 @@ export interface CreateOptions {
    * @default "typescript"
    */
   compiler?: string
+  /**
+   * Specify a custom transpiler for use with transpileOnly
+   */
+  transpiler?: string | [string, object]
   /**
    * Paths which should not be compiled.
    *
@@ -568,6 +590,24 @@ export function create (rawOptions: CreateOptions = {}): Service {
     getCanonicalFileName: ts.sys.useCaseSensitiveFileNames ? x => x : x => x.toLowerCase()
   }
 
+  if (options.transpileOnly && typeof transformers === 'function') {
+    throw new TypeError('Transformers function is unavailable in "--transpile-only"')
+  }
+  let customTranspiler: Transpiler | undefined = undefined
+  if (options.transpiler) {
+    if (!transpileOnly) throw new Error('Custom transpiler can only be used when transpileOnly is enabled.')
+    const transpilerName = typeof options.transpiler === 'string' ? options.transpiler : options.transpiler[0]
+    const transpilerOptions = typeof options.transpiler === 'string' ? {} : options.transpiler[1] ?? {}
+    // TODO mimic fixed resolution logic from loadCompiler master
+    // TODO refactor into a more generic "resolve dep relative to project" helper
+    const transpilerPath = require.resolve(transpilerName, { paths: [cwd, __dirname] })
+    const transpilerFactory: TranspilerFactory = require(transpilerPath).create
+    customTranspiler = transpilerFactory({
+      service: { options, config },
+      ...transpilerOptions
+    })
+  }
+
   // Install source map support and read from memory cache.
   sourceMapSupport.install({
     environment: 'node',
@@ -1022,17 +1062,20 @@ export function create (rawOptions: CreateOptions = {}): Service {
       }
     }
   } else {
-    if (typeof transformers === 'function') {
-      throw new TypeError('Transformers function is unavailable in "--transpile-only"')
-    }
-
     getOutput = (code: string, fileName: string): SourceOutput => {
-      const result = ts.transpileModule(code, {
-        fileName,
-        compilerOptions: config.options,
-        reportDiagnostics: true,
-        transformers: transformers
-      })
+      let result: _ts.TranspileOutput
+      if (customTranspiler) {
+        result = customTranspiler.transpile(code, {
+          fileName
+        })
+      } else {
+        result = ts.transpileModule(code, {
+          fileName,
+          compilerOptions: config.options,
+          reportDiagnostics: true,
+          transformers: transformers as _ts.CustomTransformers | undefined
+        })
+      }
 
       const diagnosticList = filterDiagnostics(result.diagnostics || [], ignoreDiagnostics)
       if (diagnosticList.length) reportTSError(diagnosticList)
@@ -1285,12 +1328,12 @@ function filterRecognizedTsConfigTsNodeOptions (jsonObject: any): TsConfigOption
   const {
     compiler, compilerHost, compilerOptions, emit, files, ignore,
     ignoreDiagnostics, logError, preferTsExts, pretty, require, skipIgnore,
-    transpileOnly, typeCheck
+    transpileOnly, typeCheck, transpiler
   } = jsonObject as TsConfigOptions
   const filteredTsConfigOptions = {
     compiler, compilerHost, compilerOptions, emit, files, ignore,
     ignoreDiagnostics, logError, preferTsExts, pretty, require, skipIgnore,
-    transpileOnly, typeCheck
+    transpileOnly, typeCheck, transpiler
   }
   // Use the typechecker to make sure this implementation has the correct set of properties
   const catchExtraneousProps: keyof TsConfigOptions = null as any as keyof typeof filteredTsConfigOptions
@@ -1308,10 +1351,11 @@ type SourceOutput = [string, string]
  */
 function updateOutput (outputText: string, fileName: string, sourceMap: string, getExtension: (fileName: string) => string) {
   const base64Map = Buffer.from(updateSourceMap(sourceMap, fileName), 'utf8').toString('base64')
-  const sourceMapContent = `data:application/json;charset=utf-8;base64,${base64Map}`
-  const sourceMapLength = `${basename(fileName)}.map`.length + (getExtension(fileName).length - extname(fileName).length)
-
-  return outputText.slice(0, -sourceMapLength) + sourceMapContent
+  const sourceMapContent = `//# sourceMappingURL=data:application/json;charset=utf-8;base64,${base64Map}`
+  // Expected form: `//# sourceMappingURL=foo.js.map` for input file foo.tsx
+  const sourceMapLength = /*//# sourceMappingURL=*/ 21 + /*foo.tsx*/ basename(fileName).length - /*.tsx*/ extname(fileName).length + /*.js*/ getExtension(fileName).length + /*.map*/ 4
+  // Only rewrite if existing directive exists, to support compilers that do not append a sourcemap directive
+  return (outputText.slice(-sourceMapLength, -sourceMapLength + 21) === '//# sourceMappingURL=' ? outputText.slice(0, -sourceMapLength) : outputText) + sourceMapContent
 }
 
 /**
@@ -1337,7 +1381,7 @@ function filterDiagnostics (diagnostics: readonly _ts.Diagnostic[], ignore: numb
  *
  * Reference: https://github.com/microsoft/TypeScript/blob/fcd9334f57d85b73dd66ad2d21c02e84822f4841/src/services/utilities.ts#L705-L731
  */
-function getTokenAtPosition (ts: typeof _ts, sourceFile: _ts.SourceFile, position: number): _ts.Node {
+function getTokenAtPosition (ts: TSCommon, sourceFile: _ts.SourceFile, position: number): _ts.Node {
   let current: _ts.Node = sourceFile
 
   outer: while (true) {