Fix cannot find module db error in JavaScript template (#3940)

* use AST to parse the config and allow blitz server to be in `src`

.changeset/light-squids-draw.md

@@ -0,0 +1,6 @@
+---
+"blitz": patch
+"@blitzjs/generator": patch
+---
+
+Fix `cannot find module db error` in JavaScript template. Replace requiring the config using `esbuild` with parsing using `jscodeshift` to get the `cliConfig` values. Added logic to find the `blitz-server` file in `src` directory 

packages/blitz/src/cli/commands/generate.ts

@@ -15,7 +15,7 @@ import {
   MutationsGenerator,
   ModelGenerator,
   QueryGenerator,
-  addCustomTemplatesBlitzConfig,
+  customTemplatesBlitzConfig,
 } from "@blitzjs/generator"
 import {log} from "../../logging"
 
@@ -65,7 +65,7 @@ const createCustomTemplates = async () => {
   })
   const templatesPathValue: string = templatesPath.value
   const isTypeScript = await getIsTypeScript()
-  addCustomTemplatesBlitzConfig(templatesPathValue, isTypeScript)
+  await customTemplatesBlitzConfig(isTypeScript, templatesPathValue, true) // to run the codemod
   log.success(`🚀 Custom templates path added/updated in app/blitz-server file`)
   const customTemplatesPath = require("path").join(process.cwd(), templatesPathValue)
   const fsExtra = await import("fs-extra")
@@ -275,20 +275,12 @@ const generate: CliCommand = async () => {
     const generators = generatorMap[selectedType as keyof typeof generatorMap]
 
     const isTypeScript = await getIsTypeScript()
-    const blitzServerPath = isTypeScript ? "app/blitz-server.ts" : "app/blitz-server.js"
-    const blitzServer = require("path").join(process.cwd(), blitzServerPath)
-    const {register} = require("esbuild-register/dist/node")
-    const {unregister} = register({
-      target: "es6",
-    })
-    const blitzConfig = require(blitzServer)
-    const {cliConfig} = blitzConfig
-    unregister()
+    const cliConfig = await customTemplatesBlitzConfig(isTypeScript)
 
     for (const GeneratorClass of generators) {
       const generator = new GeneratorClass({
         destinationRoot: require("path").resolve(),
-        templateDir: cliConfig?.customTemplates,
+        templateDir: cliConfig,
         extraArgs: args["_"].slice(3) as string[],
         modelName: singularRootContext,
         modelNames: modelNames(singularRootContext),

packages/generator/package.json

@@ -31,6 +31,7 @@
     "diff": "5.0.0",
     "enquirer": "2.3.6",
     "fs-extra": "10.0.1",
+    "globby": "13.1.2",
     "got": "^11.8.1",
     "jscodeshift": "0.13.0",
     "mem-fs": "1.2.0",

packages/generator/src/generator.ts

@@ -16,12 +16,31 @@ import {readdirRecursive} from "./utils/readdir-recursive"
 import prettier from "prettier"
 const debug = require("debug")("blitz:generator")
 
-export const addCustomTemplatesBlitzConfig = (
-  customTemplatesPath: string,
+export function getProjectRootSync() {
+  return path.dirname(getConfigSrcPath())
+}
+
+export function getConfigSrcPath() {
+  const jsPath = path.resolve(path.join(process.cwd(), "next.config.js"))
+  return jsPath
+}
+
+export const customTemplatesBlitzConfig = async (
   isTypeScript: boolean,
+  customTemplatesPath = "",
+  codemod = false,
 ) => {
-  const blitzServer = isTypeScript ? "app/blitz-server.ts" : "app/blitz-server.js"
-  const blitzServerPath = require("path").join(process.cwd(), blitzServer)
+  const {globby} = await import("globby")
+  const blitzServer = await globby(["{app,src}/**/blitz-server.{ts,js}"], {
+    cwd: getProjectRootSync(),
+  })
+  if (blitzServer.length === 0) {
+    throw new Error("Could not find blitz-server.js or blitz-server.ts in app or src folder")
+  }
+  if (blitzServer.length > 1) {
+    throw new Error("Found more than one blitz-server.js or blitz-server.ts in app or src folder")
+  }
+  const blitzServerPath = require("path").join(process.cwd(), blitzServer.at(0))
   const userConfigModuleSource = fs.readFileSync(blitzServerPath, {encoding: "utf-8"})
   const userConfigModule = j(userConfigModuleSource, {parser: customTsParser})
   const program = userConfigModule.get()
@@ -86,6 +105,9 @@ export const addCustomTemplatesBlitzConfig = (
             if (customTemplatesProperty.type === "ObjectProperty") {
               const customValue = customTemplatesProperty.value
               if (customValue.type === "StringLiteral") {
+                if (!codemod) {
+                  return customValue.value
+                }
                 customValue.value = customTemplatesPath
               }
             }
@@ -94,8 +116,10 @@ export const addCustomTemplatesBlitzConfig = (
       }
     }
   }
-  const newSource = userConfigModule.toSource()
-  fs.writeFileSync(blitzServerPath, newSource)
+  if (codemod) {
+    const newSource = userConfigModule.toSource()
+    fs.writeFileSync(blitzServerPath, newSource)
+  }
 }
 
 export const customTsParser = {