Pass an already imported module in helper

This is useful when running in environment that
transpile on the fly, such as Jest/Vitest and so
on, which don't handle the dynamic import all that
well.

Author: segevfiner

helper.d.ts

@@ -2,7 +2,7 @@ import fastify from 'fastify'
 
 declare module 'fastify-cli/helper.js' {
   module helper {
-    export function build (args: Array<string>, additionalOptions?: Object, serverOptions?: Object): ReturnType<typeof fastify>
+    export function build (args: Array<string>, additionalOptions?: Object, serverOptions?: Object, module?: Object): ReturnType<typeof fastify>
   }
 
   export = helper

helper.js

@@ -3,14 +3,14 @@
 const { runFastify } = require('./start')
 
 module.exports = {
-  build (args, additionalOptions = {}, serverOptions = {}) {
+  build (args, additionalOptions = {}, serverOptions = {}, module = undefined) {
     Object.defineProperty(additionalOptions, 'ready', {
       value: true,
       enumerable: false,
       writable: false
     })
 
-    return runFastify(args, additionalOptions, serverOptions)
+    return runFastify(args, additionalOptions, serverOptions, module)
   },
   listen: runFastify
 }

start.js

@@ -96,7 +96,7 @@ async function preloadESModules (opts) {
   })
 }
 
-async function runFastify (args, additionalOptions, serverOptions) {
+async function runFastify (args, additionalOptions, serverOptions, module) {
   const opts = parseArgs(args)
 
   if (opts.require) {
@@ -113,7 +113,11 @@ async function runFastify (args, additionalOptions, serverOptions) {
   let file = null
 
   try {
-    file = await requireServerPluginFromPath(opts._[0])
+    if (module != null) {
+      file = module
+    } else {
+      file = await requireServerPluginFromPath(opts._[0])
+    }
   } catch (e) {
     return module.exports.stop(e)
   }