feat: add ability to opt out of type gen declare statement (#3765)

* feat: add ability to opt out of type gen declare statement

* chore: docs wording

docs/typescript/generating-types.mdx

@@ -18,6 +18,32 @@ payload generate:types
 
 You can run this command whenever you need to regenerate your types, and then you can use these types in your Payload code directly.
 
+### Disable declare statement
+
+By default, `generate:types` will add a `declare` statement to your types file, which automatically enables type inference within Payload.
+
+If you are using your `payload-types.ts` file in other repos, though, it might be better to disable this `declare` statement, so that you don't get any TS errors in projects that use your Payload types, but do not have Payload installed.
+
+```ts
+// payload.config.ts
+{
+  // ...
+  typescript: {
+    declare: false, // defaults to true if not set
+  },
+}
+```
+
+If you do disable the `declare` pattern, you'll need to manually add a `declare` statement to your code in order for Payload types to be recognized. Here's an example showing how to declare your types in your `payload.config.ts` file:
+
+```ts
+import { Config } from './payload-types'
+
+declare module 'payload' {
+  export interface GeneratedTypes extends Config {}
+}
+```
+
 ### Custom output file path
 
 You can specify where you want your types to be generated by adding a property to your Payload config:

packages/payload/src/bin/generateTypes.ts

@@ -2,8 +2,6 @@
 import fs from 'fs'
 import { compile } from 'json-schema-to-typescript'
 
-import type { SanitizedCollectionConfig, SanitizedGlobalConfig } from '../exports/types'
-
 import payload from '..'
 import loadConfig from '../config/load'
 import { configToJSONSchema } from '../utilities/configToJSONSchema'
@@ -25,8 +23,8 @@ export async function generateTypes(): Promise<void> {
 
   const jsonSchema = configToJSONSchema(payload.config, payload.db.defaultIDType)
 
-  const declare = `declare module "payload" {\n  export interface GeneratedTypes extends Config {}\n}`
-  
+  const declare = `declare module 'payload' {\n  export interface GeneratedTypes extends Config {}\n}`
+
   compile(jsonSchema, 'Config', {
     bannerComment:
       '/* tslint:disable */\n/* eslint-disable */\n/**\n* This file was automatically generated by Payload.\n* DO NOT MODIFY IT BY HAND. Instead, modify your source Payload config,\n* and re-run `payload generate:types` to regenerate this file.\n*/',
@@ -34,7 +32,10 @@ export async function generateTypes(): Promise<void> {
       singleQuote: true,
     },
   }).then((compiled) => {
-    fs.writeFileSync(outputFile, `${compiled}\n\n${declare}`)
+    if (config.typescript.declare !== false) {
+      compiled += `\n\n${declare}`
+    }
+    fs.writeFileSync(outputFile, compiled)
     logger.info(`Types written to ${outputFile}`)
   })
 }

packages/payload/src/config/schema.ts

@@ -178,6 +178,7 @@ export default joi.object({
     }),
   telemetry: joi.boolean(),
   typescript: joi.object({
+    declare: joi.boolean(),
     outputFile: joi.string(),
   }),
   upload: joi.object(),

packages/payload/src/config/types.ts

@@ -660,6 +660,8 @@ export type Config = {
   telemetry?: boolean
   /** Control how typescript interfaces are generated from your collections. */
   typescript?: {
+    /** Disable declare block in generated types file */
+    declare?: false
     /** Filename to write the generated types to */
     outputFile?: string
   }