fix: import function template metadata as module (#6516)

* fix: rename .netlify-function-template.js -> .mjs

* test: create typescript serverless function

* test: test typescript outside of nx fixture

---------

Co-authored-by: kodiakhq[bot] <49736102+kodiakhq[bot]@users.noreply.github.com>

src/commands/functions/functions-create.ts

@@ -115,7 +115,7 @@ const formatRegistryArrayForInquirer = async function (lang, funcType) {
       .filter((folder) => Boolean(folder?.isDirectory()))
       .map(async ({ name }) => {
         try {
-          const templatePath = path.join(templatesDir, lang, name, '.netlify-function-template.js')
+          const templatePath = path.join(templatesDir, lang, name, '.netlify-function-template.mjs')
           // @ts-expect-error TS(7036) FIXME: Dynamic import's specifier must be of type 'string... Remove this comment to see the full error message
           const template = await import(pathToFileURL(templatePath))
           return template.default
@@ -393,7 +393,7 @@ const downloadFromURL = async function (command, options, argumentName, function
   })
 
   // read, execute, and delete function template file if exists
-  const fnTemplateFile = path.join(fnFolder, '.netlify-function-template.js')
+  const fnTemplateFile = path.join(fnFolder, '.netlify-function-template.mjs')
   if (await fileExistsAsync(fnTemplateFile)) {
     const {
       default: { addons = [], onComplete },
@@ -521,7 +521,7 @@ const scaffoldFromTemplate = async function (command, options, argumentName, fun
 
     // These files will not be part of the log message because they'll likely
     // be removed before the command finishes.
-    const omittedFromOutput = new Set(['.netlify-function-template.js', 'package.json', 'package-lock.json'])
+    const omittedFromOutput = new Set(['.netlify-function-template.mjs', 'package.json', 'package-lock.json'])
     const createdFiles = await copyTemplateDir(pathToTemplate, functionPath, vars)
     // @ts-expect-error TS(7006) FIXME: Parameter 'filePath' implicitly has an 'any' type.
     createdFiles.forEach((filePath) => {
@@ -538,7 +538,7 @@ const scaffoldFromTemplate = async function (command, options, argumentName, fun
     })
 
     // delete function template file that was copied over by copydir
-    await unlink(path.join(functionPath, '.netlify-function-template.js'))
+    await unlink(path.join(functionPath, '.netlify-function-template.mjs'))
 
     // npm install
     if (functionPackageJson !== undefined) {

tests/integration/commands/functions-create/functions-create.test.ts

@@ -181,42 +181,46 @@ describe.concurrent('functions:create command', () => {
   })
 
   test('should only show function templates for the language specified via the --language flag, if one is present', async () => {
-    await withSiteBuilder('site-with-no-functions-dir', async (builder) => {
-      await builder.buildAsync()
+    const createWithLanguageTemplate = async (language, outputPath) =>
+      await withSiteBuilder('site-with-no-functions-dir', async (builder) => {
+        await builder.buildAsync()
 
-      const createFunctionQuestions = [
-        {
-          question: "Select the type of function you'd like to create",
-          answer: answerWithValue(DOWN),
-        },
-        {
-          question: 'Enter the path, relative to your site',
-          answer: answerWithValue('test/functions'),
-        },
-        {
-          question: 'Pick a template',
-          answer: CONFIRM,
-        },
-        {
-          question: 'Name your function',
-          answer: CONFIRM,
-        },
-      ]
+        const createFunctionQuestions = [
+          {
+            question: "Select the type of function you'd like to create",
+            answer: answerWithValue(DOWN),
+          },
+          {
+            question: 'Enter the path, relative to your site',
+            answer: answerWithValue('test/functions'),
+          },
+          {
+            question: 'Pick a template',
+            answer: CONFIRM,
+          },
+          {
+            question: 'Name your function',
+            answer: CONFIRM,
+          },
+        ]
 
-      await withMockApi(routes, async ({ apiUrl }) => {
-        const childProcess = execa(
-          cliPath,
-          ['functions:create', '--language', 'javascript'],
-          getCLIOptions({ apiUrl, builder }),
-        )
+        await withMockApi(routes, async ({ apiUrl }) => {
+          const childProcess = execa(
+            cliPath,
+            ['functions:create', '--language', language],
+            getCLIOptions({ apiUrl, builder }),
+          )
 
-        handleQuestions(childProcess, createFunctionQuestions)
+          handleQuestions(childProcess, createFunctionQuestions)
 
-        await childProcess
+          await childProcess
 
-        expect(await fileExistsAsync(`${builder.directory}/test/functions/hello-world/hello-world.js`)).toBe(true)
+          expect(await fileExistsAsync(`${builder.directory}/test/functions/${outputPath}`)).toBe(true)
+        })
       })
-    })
+
+    await createWithLanguageTemplate('javascript', 'hello-world/hello-world.js')
+    await createWithLanguageTemplate('typescript', 'hello-world/hello-world.ts')
   })
 
   test('throws an error when the --language flag contains an unsupported value', async () => {