improves baseUrl resolution in typescript monorepos

Typescript configuration can inherit from files above cwd in the
filesystem. If a baseUrl was declared in such a file, it would not be
picked up by the webpack config. This would force users to use the
next-transpile-module and duplicate configuration with unintuitive path
relations (see #13197 for a detailed analysis)

If baseUrl is resolved it should be used instead of dir as the root
include for babel-resolve-loader.

Author: jeantil

packages/next/build/webpack-config.ts

@@ -15,6 +15,7 @@ import {
 } from '../lib/constants'
 import { fileExists } from '../lib/file-exists'
 import { resolveRequest } from '../lib/resolve-request'
+import { getTypeScriptConfiguration } from '../lib/typescript/getTypeScriptConfiguration'
 import {
   CLIENT_STATIC_FILES_RUNTIME_MAIN,
   CLIENT_STATIC_FILES_RUNTIME_POLYFILLS,
@@ -261,7 +262,9 @@ export default async function getBaseWebpackConfig(
   let jsConfig
   // jsconfig is a subset of tsconfig
   if (useTypeScript) {
-    jsConfig = parseJsonFile(tsConfigPath)
+    const ts = (await import(typeScriptPath)) as typeof import('typescript')
+    const tsConfig = await getTypeScriptConfiguration(ts, tsConfigPath)
+    jsConfig = { compilerOptions: tsConfig.options }
   }
 
   const jsConfigPath = path.join(dir, 'jsconfig.json')

test/integration/typescript-workspaces-paths/packages/lib/a/api.ts

@@ -0,0 +1,5 @@
+//this line uses typescript specific syntax
+//to demonstrate that transpilation occurs
+export type API = () => string
+const api: API = () => 'Hello from a'
+export default api

test/integration/typescript-workspaces-paths/packages/lib/b/api.ts

@@ -0,0 +1,4 @@
+import { API } from '@lib/api'
+
+const b: API = () => 'Hello from b'
+export default b

test/integration/typescript-workspaces-paths/packages/lib/b/b-only.ts

@@ -0,0 +1,4 @@
+import { API } from '@lib/api'
+
+const b: API = () => 'Hello from only b'
+export default b

test/integration/typescript-workspaces-paths/packages/www/components/alias-to-d-ts.d.ts

@@ -0,0 +1 @@
+export default () => any

test/integration/typescript-workspaces-paths/packages/www/components/alias-to-d-ts.tsx

@@ -0,0 +1,4 @@
+const Named = () => {
+  return <>Not aliased to d.ts file</>
+}
+export default Named

test/integration/typescript-workspaces-paths/packages/www/components/hello.tsx

@@ -0,0 +1,5 @@
+import React from 'react'
+
+export function Hello() {
+  return <>Hello</>
+}

test/integration/typescript-workspaces-paths/packages/www/components/world.tsx

@@ -0,0 +1,5 @@
+import React from 'react'
+
+export function World(): JSX.Element {
+  return <>World</>
+}

test/integration/typescript-workspaces-paths/packages/www/next.config.js

@@ -0,0 +1,23 @@
+const path = require('path')
+module.exports = {
+  webpack: function (config, { defaultLoaders }) {
+    const resolvedBaseUrl = path.resolve(config.context, '../../')
+    config.module.rules = [
+      ...config.module.rules,
+      {
+        test: /\.(tsx|ts|js|mjs|jsx)$/,
+        include: [resolvedBaseUrl],
+        use: defaultLoaders.babel,
+        exclude: (excludePath) => {
+          return /node_modules/.test(excludePath)
+        },
+      },
+    ]
+    return config
+  },
+
+  onDemandEntries: {
+    // Make sure entries are not getting disposed.
+    maxInactiveAge: 1000 * 60 * 60,
+  },
+}

test/integration/typescript-workspaces-paths/packages/www/pages/alias-to-d-ts.tsx

@@ -0,0 +1,10 @@
+import React from 'react'
+import NotAliasedToDTS from 'd-ts-alias'
+
+export default function HelloPage(): JSX.Element {
+  return (
+    <div>
+      <NotAliasedToDTS />
+    </div>
+  )
+}