differentiate between partial and full next config objects

Author: lobsterkatie

packages/nextjs/src/config/index.ts

@@ -11,11 +11,11 @@ import { constructWebpackConfigFunction } from './webpack';
 export function withSentryConfig(
   userNextConfig: ExportedNextConfig = {},
   userSentryWebpackPluginOptions: Partial<SentryWebpackPluginOptions> = {},
-): NextConfigFunction | NextConfigObject {
+): NextConfigFunction | Partial<NextConfigObject> {
   // If the user has passed us a function, we need to return a function, so that we have access to `phase` and
   // `defaults` in order to pass them along to the user's function
   if (typeof userNextConfig === 'function') {
-    return function(phase: string, defaults: { defaultConfig: NextConfigObject }): NextConfigObject {
+    return function(phase: string, defaults: { defaultConfig: NextConfigObject }): Partial<NextConfigObject> {
       const materializedUserNextConfig = userNextConfig(phase, defaults);
       return {
         ...materializedUserNextConfig,

packages/nextjs/src/config/types.ts

@@ -7,13 +7,13 @@ export type SentryWebpackPlugin = { options: SentryWebpackPluginOptions };
  * Overall Nextjs config
  */
 
-export type ExportedNextConfig = NextConfigObject | NextConfigFunction;
+export type ExportedNextConfig = Partial<NextConfigObject> | NextConfigFunction;
 
 export type NextConfigObject = {
   // custom webpack options
-  webpack?: WebpackConfigFunction;
+  webpack: WebpackConfigFunction;
   // whether to build serverless functions for all pages, not just API routes
-  target?: 'server' | 'experimental-serverless-trace';
+  target: 'server' | 'experimental-serverless-trace';
   sentry?: {
     disableServerWebpackPlugin?: boolean;
     disableClientWebpackPlugin?: boolean;
@@ -25,8 +25,8 @@ export type NextConfigObject = {
 
 export type NextConfigFunction = (
   phase: string,
-  defaults: { defaultConfig: { [key: string]: unknown } },
-) => NextConfigObject;
+  defaults: { defaultConfig: NextConfigObject },
+) => Partial<NextConfigObject>;
 
 /**
  * Webpack config
@@ -56,7 +56,7 @@ export type BuildContext = {
   isServer: boolean;
   buildId: string;
   dir: string;
-  config: Partial<NextConfigObject>;
+  config: NextConfigObject;
   webpack: { version: string };
 };
 

packages/nextjs/src/config/webpack.ts

@@ -34,7 +34,7 @@ export { SentryWebpackPlugin };
  * @returns The function to set as the nextjs config's `webpack` value
  */
 export function constructWebpackConfigFunction(
-  userNextConfig: NextConfigObject = {},
+  userNextConfig: Partial<NextConfigObject> = {},
   userSentryWebpackPluginOptions: Partial<SentryWebpackPluginOptions> = {},
 ): WebpackConfigFunction {
   // Will be called by nextjs and passed its default webpack configuration and context data about the build (whether

packages/nextjs/test/config.test.ts

@@ -58,7 +58,7 @@ process.env.SENTRY_RELEASE = 'doGsaREgReaT';
 const runtimePhase = 'ball-fetching';
 // `defaultConfig` is the defaults for all nextjs options (we don't use these at all in the tests, so for our purposes
 // here the values don't matter)
-const defaultsObject = { defaultConfig: {} };
+const defaultsObject = { defaultConfig: {} as NextConfigObject };
 
 /** mocks of the arguments passed to `nextConfig.webpack` */
 const serverWebpackConfig = {
@@ -103,7 +103,7 @@ function getBuildContext(
     dev: false,
     buildId: 'sItStAyLiEdOwN',
     dir: '/Users/Maisey/projects/squirrelChasingSimulator',
-    config: { target: 'server', ...userNextConfig },
+    config: { target: 'server', ...userNextConfig } as NextConfigObject,
     webpack: { version: webpackVersion },
     isServer: buildTarget === 'server',
   };