feat: support inline arrow function

Author: sxzz

src/core/index.ts

@@ -14,6 +14,9 @@ import {
 } from 'magic-string-ast'
 import type * as t from '@babel/types'
 
+const ARROW_FN_START = `\nreturn function* () {`
+const ARROW_FN_END = `}.call(this)\n`
+
 export function transformQuansync(
   code: string,
   id: string,
@@ -75,10 +78,11 @@ export function transformQuansync(
         }
 
         if (node.body.type === 'BlockStatement') {
-          s.appendLeft(node.body.start! + 1, `\nreturn function* () {`)
-          s.appendLeft(node.body.end! - 1, `}.call(this)\n`)
+          s.appendLeft(node.body.start! + 1, ARROW_FN_START)
+          s.appendLeft(node.body.end! - 1, ARROW_FN_END)
         } else {
-          throw new SyntaxError('Inlined arrow function is not supported')
+          s.appendLeft(node.body.start!, `{${ARROW_FN_START}\nreturn `)
+          s.appendLeft(node.body.end!, `\n${ARROW_FN_END}}`)
         }
       } else if (firstParam) {
         s.overwrite(node.start!, firstParam.start!, `function* ${name}(`)

tests/__snapshots__/transform.test.ts.snap

@@ -106,3 +106,35 @@ export default async () => {
 }
 "
 `;
+
+exports[`transform > ./fixtures/inlined-arrow.js 1`] = `
+"import { toGenerator as _QUANSYNC_TO_GEN } from 'quansync'
+// @ts-check
+import { quansyncMacro } from 'quansync'
+import { expect } from 'vitest'
+
+export const echo = quansyncMacro({
+  sync: /** @param {string} v */ (v) => v,
+  async: (v) => Promise.resolve(v),
+})
+
+const echoNewLine = quansyncMacro(
+  /** @param {string|Promise<string>} v */ (v) =>
+    {
+return function* () {
+return (yield * _QUANSYNC_TO_GEN(echo(yield * _QUANSYNC_TO_GEN(v)))) + '\\n'
+}.call(this)
+},
+)
+
+export default async () => {
+  const iter = echoNewLine('hello')
+  expect(iter).a('Generator')
+  await expect(iter).resolves.toBe('hello\\n')
+  expect(echoNewLine.sync('world')).toBe('world\\n')
+
+  await expect(echoNewLine(Promise.resolve('hello'))).resolves.toBe('hello\\n')
+  expect(() => echoNewLine.sync(Promise.resolve('world'))).throw()
+}
+"
+`;

tests/fixtures/inlined-arrow.js

@@ -0,0 +1,23 @@
+// @ts-check
+import { quansyncMacro } from 'quansync'
+import { expect } from 'vitest'
+
+export const echo = quansyncMacro({
+  sync: /** @param {string} v */ (v) => v,
+  async: (v) => Promise.resolve(v),
+})
+
+const echoNewLine = quansyncMacro(
+  /** @param {string|Promise<string>} v */ async (v) =>
+    (await echo(await v)) + '\n',
+)
+
+export default async () => {
+  const iter = echoNewLine('hello')
+  expect(iter).a('Generator')
+  await expect(iter).resolves.toBe('hello\n')
+  expect(echoNewLine.sync('world')).toBe('world\n')
+
+  await expect(echoNewLine(Promise.resolve('hello'))).resolves.toBe('hello\n')
+  expect(() => echoNewLine.sync(Promise.resolve('world'))).throw()
+}