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reactjsnext.js

TypeError: Class extends value undefined is not a constructor or null while running next.js

While running

npm run dev

I suddenly start getting error without pretty much any change to the code of the project:

TypeError: Class extends value undefined is not a constructor or null
    at Object.618 (/Users/EugeneBos/Websites/dotalaning/node_modules/next/dist/compiled/postcss-scss/scss-syntax.js:1:100)
    at __nccwpck_require__ (/Users/EugeneBos/Websites/dotalaning/node_modules/next/dist/compiled/postcss-scss/scss-syntax.js:1:11735)
    at Object.270 (/Users/EugeneBos/Websites/dotalaning/node_modules/next/dist/compiled/postcss-scss/scss-syntax.js:1:413)
    at __nccwpck_require__ (/Users/EugeneBos/Websites/dotalaning/node_modules/next/dist/compiled/postcss-scss/scss-syntax.js:1:11735)
    at Object.327 (/Users/EugeneBos/Websites/dotalaning/node_modules/next/dist/compiled/postcss-scss/scss-syntax.js:1:260)
    at __nccwpck_require__ (/Users/EugeneBos/Websites/dotalaning/node_modules/next/dist/compiled/postcss-scss/scss-syntax.js:1:11735)
    at Object.845 (/Users/EugeneBos/Websites/dotalaning/node_modules/next/dist/compiled/postcss-scss/scss-syntax.js:1:3733)
    at __nccwpck_require__ (/Users/EugeneBos/Websites/dotalaning/node_modules/next/dist/compiled/postcss-scss/scss-syntax.js:1:11735)
    at /Users/EugeneBos/Websites/dotalaning/node_modules/next/dist/compiled/postcss-scss/scss-syntax.js:1:11863
    at Object.<anonymous> (/Users/EugeneBos/Websites/dotalaning/node_modules/next/dist/compiled/postcss-scss/scss-syntax.js:1:11889)
    at Module._compile (node:internal/modules/cjs/loader:1108:14)
    at Object.Module._extensions..js (node:internal/modules/cjs/loader:1137:10)
    at Module.load (node:internal/modules/cjs/loader:973:32)
    at Function.Module._load (node:internal/modules/cjs/loader:813:14)
    at Module.require (node:internal/modules/cjs/loader:997:19)
    at require (node:internal/modules/cjs/helpers:92:18)

Modifying the code of the app so it won't include any files or load anything still produces the same error.

Solution

  • 1 Try removing node_modules and installing everything again have helped.

    rm -rf node_modules
npm install

    2 The problem may be caused by the version of Node JS (too old or too new). In this case, you may change it with n or nvm (the latest has a version for Windows too)