simplify NextConfigObject type

Author: lobsterkatie

packages/nextjs/src/config/index.ts

@@ -1,4 +1,4 @@
-import { ExportedNextConfig, NextConfigFunction, NextConfigObject, SentryWebpackPluginOptions } from './types';
+import type { ExportedNextConfig, NextConfigFunction, NextConfigObject, SentryWebpackPluginOptions } from './types';
 import { constructWebpackConfigFunction } from './webpack';
 
 /**
@@ -11,11 +11,11 @@ import { constructWebpackConfigFunction } from './webpack';
 export function withSentryConfig(
   userNextConfig: ExportedNextConfig = {},
   userSentryWebpackPluginOptions: Partial<SentryWebpackPluginOptions> = {},
-): NextConfigFunction | Partial<NextConfigObject> {
+): NextConfigFunction | 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 }): Partial<NextConfigObject> {
+    return function (phase: string, defaults: { defaultConfig: NextConfigObject }): NextConfigObject {
       const materializedUserNextConfig = userNextConfig(phase, defaults);
 
       // Next 12.2.3+ warns about non-canonical properties on `userNextConfig`, so grab and then remove the `sentry`

packages/nextjs/src/config/types.ts

@@ -8,21 +8,18 @@ export type SentryWebpackPlugin = WebpackPluginInstance & { options: SentryWebpa
  * Overall Nextjs config
  */
 
-export type ExportedNextConfig = Partial<NextConfigObject> | NextConfigFunction;
+export type ExportedNextConfig = 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';
   // the output directory for the built app (defaults to ".next")
-  distDir: string;
+  distDir?: string;
   // the root at which the nextjs app will be served (defaults to "/")
-  basePath: string;
+  basePath?: string;
   sentry?: UserSentryOptions;
-} & {
-  // other `next.config.js` options
-  [key: string]: unknown;
 };
 
 export type UserSentryOptions = {
@@ -42,10 +39,7 @@ export type UserSentryOptions = {
   widenClientFileUpload?: boolean;
 };
 
-export type NextConfigFunction = (
-  phase: string,
-  defaults: { defaultConfig: NextConfigObject },
-) => Partial<NextConfigObject>;
+export type NextConfigFunction = (phase: string, defaults: { defaultConfig: NextConfigObject }) => NextConfigObject;
 
 /**
  * Webpack config

packages/nextjs/src/config/webpack.ts

@@ -36,7 +36,7 @@ export { SentryWebpackPlugin };
  * @returns The function to set as the nextjs config's `webpack` value
  */
 export function constructWebpackConfigFunction(
-  userNextConfig: Partial<NextConfigObject> = {},
+  userNextConfig: NextConfigObject = {},
   userSentryWebpackPluginOptions: Partial<SentryWebpackPluginOptions> = {},
   userSentryOptions: UserSentryOptions = {},
 ): WebpackConfigFunction {

packages/nextjs/test/config.test.ts

@@ -64,7 +64,7 @@ afterEach(() => {
 });
 
 /** Mocks of the arguments passed to `withSentryConfig` */
-const userNextConfig: Partial<NextConfigObject> = {
+const userNextConfig: NextConfigObject = {
   publicRuntimeConfig: { location: 'dogpark', activities: ['fetch', 'chasing', 'digging'] },
   webpack: (config: WebpackConfigObject, _options: BuildContext) => ({
     ...config,
@@ -124,7 +124,7 @@ const clientWebpackConfig = {
 // dynamically.
 function getBuildContext(
   buildTarget: 'server' | 'client',
-  userNextConfig: Partial<NextConfigObject>,
+  userNextConfig: NextConfigObject,
   webpackVersion: string = '5.4.15',
 ): BuildContext {
   return {