compilerOptions key is not provided, when using next.config.ts #75699Description
Link to the code that reproduces this issue
https://codesandbox.io/p/devbox/stoic-joji-4sljq7?file=%2Ftsconfig.json%3A5%2C1
To Reproduce
- Use
next.config.tsin Next 15 - Have a tsconfig.json without a
compilerOptionskey
for example, we have
{
"extends": ["tsconfig/base.json", "tsconfig/nextjs.json"],
"include": ["next-env.d.ts", "**/*.ts", "**/*.tsx"],
"exclude": ["node_modules"],
}
where compilerOptions is defined in base.json, but not directly in the file.
- Run
next dev - See this error
/Users/giles/code/retool-web/node_modules/.pnpm/next@15.1.6_@babel+core@7.26.0_babel-plugin-macros@3.1.0_react-dom@19.0.0_react@19.0.0__react@19.0.0_sass@1.80.5/node_modules/next/dist/build/next-config-ts/transpile-config.js:16
const resolvedBaseUrl = (0, _nodepath.join)(cwd, compilerOptions.baseUrl ?? '.');
^
TypeError: Cannot read properties of undefined (reading 'baseUrl')
at resolveSWCOptions (/Users/giles/code/retool-web/node_modules/.pnpm/next@15.1.6_@babel+core@7.26.0_babel-plugin-macros@3.1.0_react-dom@19.0.0_react@19.0.0__react@19.0.0_sass@1.80.5/node_modules/next/dist/build/next-config-ts/transp
71F8
ile-config.js:16:70)
at transpileConfig (/Users/giles/code/retool-web/node_modules/.pnpm/next@15.1.6_@babel+core@7.26.0_babel-plugin-macros@3.1.0_react-dom@19.0.0_react@19.0.0__react@19.0.0_sass@1.80.5/node_modules/next/dist/build/next-config-ts/transpile-config.js:51:28)
at async loadConfig (/Users/giles/code/retool-web/node_modules/.pnpm/next@15.1.6_@babel+core@7.26.0_babel-plugin-macros@3.1.0_react-dom@19.0.0_react@19.0.0__react@19.0.0_sass@1.80.5/node_modules/next/dist/server/config.js:771:36)
at async Module.nextDev (/Users/giles/code/retool-web/node_modules/.pnpm/next@15.1.6_@babel+core@7.26.0_babel-plugin-macros@3.1.0_react-dom@19.0.0_react@19.0.0__react@19.0.0_sass@1.80.5/node_modules/next/dist/cli/next-dev.js:190:14)
Coming from here https://github.com/vercel/next.js/blob/canary/packages/next/src/build/next-config-ts/transpile-config.ts#L53
Current vs. Expected behavior
Expected Next to work without this key
Actually it crashed.
Provide environment information
Operating System:
Platform: darwin
Arch: arm64
Version: Darwin Kernel Version 24.3.0: Thu Jan 2 20:24:23 PST 2025; root:xnu-11215.81.4~3/RELEASE_ARM64_T6031
Available memory (MB): 36864
Available CPU cores: 14
Binaries:
Node: 22.11.0
npm: 10.9.0
Yarn: N/A
pnpm: 9.14.2
Relevant Packages:
next: 15.1.6 // Latest available version is detected (15.1.6).
eslint-config-next: N/A
react: 19.0.0
react-dom: 19.0.0
typescript: 5.7.3
Next.js Config:
output: N/AWhich area(s) are affected? (Select all that apply)
TypeScript
Which stage(s) are affected? (Select all that apply)
next dev (local), next build (local), next start (local)
Additional context
No response