fix(features): fix magicast function body manipulation

magicast's $body.push() doesn't work for function-expression types.
Created addStatementToFunctionBody helper that directly manipulates
the AST to properly add plugin registrations to registerPlugins.

Author: johnleider

packages/shared/src/features/i18n.ts

@@ -4,6 +4,7 @@ import { writeFile } from 'node:fs/promises'
 import { join } from 'node:path'
 import { loadFile } from 'magicast'
 import { getDefaultExportOptions } from 'magicast/helpers'
+import { addStatementToFunctionBody, isFunction } from '../utils/magicast'
 import rootPkg from './dependencies/package.json' with { type: 'json' }
 
 export const i18n: Feature = {
@@ -56,8 +57,8 @@ export const i18n: Feature = {
         })
 
         const registerPlugins = mod.exports.registerPlugins
-        if (registerPlugins && registerPlugins.$type === 'function') {
-          registerPlugins.$body.push('app.use(i18n)')
+        if (isFunction(registerPlugins)) {
+          addStatementToFunctionBody(registerPlugins, 'app.use(i18n)')
         }
 
         await writeFile(pluginsPath, mod.generate().code)

packages/shared/src/features/pinia.ts

@@ -4,6 +4,7 @@ import { writeFile } from 'node:fs/promises'
 import { join } from 'node:path'
 import { loadFile } from 'magicast'
 import { getDefaultExportOptions } from 'magicast/helpers'
+import { addStatementToFunctionBody, isFunction } from '../utils/magicast'
 import rootPkg from './dependencies/package.json' with { type: 'json' }
 
 export const pinia: Feature = {
@@ -62,8 +63,8 @@ export const pinia: Feature = {
       })
 
       const registerPlugins = mod.exports.registerPlugins
-      if (registerPlugins && registerPlugins.$type === 'function') {
-        registerPlugins.$body.push('app.use(createPinia())')
+      if (isFunction(registerPlugins)) {
+        addStatementToFunctionBody(registerPlugins, 'app.use(createPinia())')
       }
 
       await writeFile(pluginsPath, mod.generate().code)

packages/shared/src/features/router.ts

@@ -4,6 +4,7 @@ import { writeFile } from 'node:fs/promises'
 import { join } from 'node:path'
 import { builders, loadFile } from 'magicast'
 import { installFeature } from '../utils/installFeature'
+import { addStatementToFunctionBody, isFunction } from '../utils/magicast'
 import rootPkg from './dependencies/package.json' with { type: 'json' }
 
 export const router: Feature = {
@@ -33,8 +34,8 @@ export const router: Feature = {
     })
 
     const registerPlugins = mod.exports.registerPlugins
-    if (registerPlugins && registerPlugins.$type === 'function') {
-      registerPlugins.$body.push('app.use(router)')
+    if (isFunction(registerPlugins)) {
+      addStatementToFunctionBody(registerPlugins, 'app.use(router)')
     }
 
     await writeFile(pluginsPath, mod.generate().code)
@@ -70,8 +71,8 @@ export const fileRouter: Feature = {
     })
 
     const registerPlugins = mod.exports.registerPlugins
-    if (registerPlugins && registerPlugins.$type === 'function') {
-      registerPlugins.$body.push('app.use(router)')
+    if (isFunction(registerPlugins)) {
+      addStatementToFunctionBody(registerPlugins, 'app.use(router)')
     }
 
     await writeFile(pluginsPath, mod.generate().code)

packages/shared/src/utils/magicast.ts

@@ -0,0 +1,27 @@
+import { parseExpression } from 'magicast'
+
+/**
+ * Adds a statement to a function body using AST manipulation.
+ * magicast's $body.push() doesn't work for function-expression types,
+ * so we need to manipulate the AST directly.
+ */
+export function addStatementToFunctionBody (fn: any, statement: string) {
+  if (!fn || !fn.$ast?.body?.body) return false
+
+  const expr = parseExpression(statement)
+  const newStatement = {
+    type: 'ExpressionStatement',
+    expression: expr.$ast,
+    loc: null,
+  }
+
+  fn.$ast.body.body.push(newStatement)
+  return true
+}
+
+/**
+ * Checks if the export is a function (either 'function' or 'function-expression')
+ */
+export function isFunction (fn: any): boolean {
+  return fn && (fn.$type === 'function' || fn.$type === 'function-expression')
+}