feat: sync. (#2)

README.md

@@ -14,9 +14,11 @@ Provides a workaround for [swc/1366](https://github.com/swc-project/swc/issues/1
 
 ## Example
 
+There are four exports `reparse`, `reparseFile`, `reparseSync` and `reparseFileSync`.
+
 ```js
-import assert from 'node:assert/strict'
 import { reparse } from '@knighted/reparse'
+import assert from 'node:assert/strict'
 
 const ast1 = await reparse('const foo = "bar"')
 const ast2 = await reparse('const foo = "bar"')
@@ -25,19 +27,13 @@ assert.equal(ast1.span.start, ast2.span.start)
 assert.equal(ast1.span.end, ast2.span.end)
 ```
 
-You can also pass a file to `reparseFile`.
-
-## Notes
-
-This package makes use of [`child_process.fork()`](https://nodejs.org/api/child_process.html#child_processforkmodulepath-args-options) for each invokation of `reparse()`. Thus it makes use of a promise to resolve the response from the forked child process which does the parsing, so the functions provided from `@knighted/reparse` are both async.
-
-If you are consuming this package from CommonJS you need to wrap calls to `reparse` and `reparseFile` in an `async` function since top level await is not available.
+Sync file example:
 
 ```js
-const { reparse } = require('@knighted/reparse')
-const doReparse = async () => {
-  const ast = await reparse('const foo = "bar"')
-}
+import { reparseFileSync } from '@knighted/reparse'
+
+const ast0 = reparseFileSync('./file.ts')
+const ast1 = reparseFileSync('./file.ts')
 
-doReparse()
+console.log(ast0.span.start === ast1.span.start) // true
 ```

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@knighted/reparse",
-  "version": "1.0.0",
+  "version": "1.1.0",
   "description": "Multiple swc parsings of the same file with correct spans.",
   "type": "module",
   "main": "dist/reparse.js",

postbuild.ts

@@ -5,4 +5,4 @@ const dist = resolve(import.meta.dirname, 'dist')
 const reparseCjs = join(dist, 'cjs', 'reparse.cjs')
 const cjs = (await readFile(reparseCjs)).toString()
 
-await writeFile(reparseCjs, cjs.replace(/child\.js/, 'child.cjs'))
+await writeFile(reparseCjs, cjs.replace(/child\.js/, 'child.cjs').replace(/childSync\.js/, 'childSync.cjs'))

src/childSync.js

@@ -0,0 +1,26 @@
+import { argv, stdout } from 'node:process'
+
+import { parseSync, parseFileSync } from '@swc/core'
+
+const baseConfig = {
+  comments: false,
+  target: 'esnext',
+  isModule: true,
+}
+const tsConfig = {
+  syntax: 'typescript',
+  tsx: true,
+}
+const esConfig = {
+  syntax: 'ecmascript',
+  jsx: true,
+  importAttributes: true,
+}
+const parse = () => {
+  const parseOptions = Object.assign(baseConfig, argv[3] === 'es' ? esConfig : tsConfig)
+  const ast = argv[4] === 'file' ? parseFileSync(argv[2], parseOptions) : parseSync(argv[2], parseOptions)
+
+  stdout.write(JSON.stringify(ast))
+}
+
+parse()

src/reparse.ts

@@ -1,4 +1,4 @@
-import { fork } from 'node:child_process'
+import { fork, spawnSync } from 'node:child_process'
 import { join } from 'node:path'
 
 import type { Module } from '@swc/core'
@@ -12,14 +12,7 @@ const isModule = (msg: unknown): msg is Module => {
 
   return false
 }
-
 const forkChild = (...args: string[]) => {
-  /**
-   * Circumvent SWC double parse span bug where start/end line numbers
-   * are wrong on subsequent parsings.
-   *
-   * @see https://github.com/swc-project/swc/issues/1366
-   */
   const child = fork(join(import.meta.dirname, 'child.js'), [...args], {
     serialization: 'advanced',
   })
@@ -37,9 +30,21 @@ const forkChild = (...args: string[]) => {
     })
   })
 }
+const spawnChild = (...args: string[]) => {
+  const { stdout } = spawnSync('node', [join(import.meta.dirname, 'childSync.js'), ...args])
+  const ast = JSON.parse(stdout.toString()) as Module
+
+  return ast
+}
 export const reparse = (source: string, lang: Lang = 'ts') => {
   return forkChild(source, lang)
 }
 export const reparseFile = (file: string, lang: Lang = 'ts') => {
   return forkChild(file, lang, 'file')
 }
+export const reparseSync = (source: string, lang: Lang = 'ts') => {
+  return spawnChild(source, lang)
+}
+export const reparseFileSync = (file: string, lang: Lang = 'ts') => {
+  return spawnChild(file, lang, 'file')
+}

test/reparse.ts

@@ -2,7 +2,7 @@ import { describe, it } from 'node:test'
 import assert from 'node:assert/strict'
 import { resolve, join } from 'node:path'
 
-import { reparse, reparseFile } from '../src/reparse.js'
+import { reparse, reparseFile, reparseSync, reparseFileSync } from '../src/reparse.js'
 
 const fixtures = resolve(import.meta.dirname, 'fixtures')
 
@@ -18,4 +18,16 @@ describe('@knighted/reparse', () => {
     assert.equal(ast3.span.start, ast4.span.start)
     assert.equal(ast3.span.end, ast4.span.end)
   })
+
+  it('returns correct spans with multiple swc parsings synchronously', () => {
+    const ast1 = reparseSync('const foo = "bar"')
+    const ast2 = reparseSync('const foo = "bar"')
+    const ast3 = reparseFileSync(join(fixtures, 'file.ts'))
+    const ast4 = reparseFileSync(join(fixtures, 'file.ts'))
+
+    assert.equal(ast1.span.start, ast2.span.start)
+    assert.equal(ast1.span.end, ast2.span.end)
+    assert.equal(ast3.span.start, ast4.span.start)
+    assert.equal(ast3.span.end, ast4.span.end)
+  })
 })