TS17004: Cannot use JSX unless the jsx flag is provided - in CI

By Daniel Zoghalchali·Latchkey

A file contains JSX but the tsconfig does not enable JSX compilation.

What this error means

Type-checking fails with TS17004 at the first JSX element because the jsx option is unset.

src/App.tsx(4,10): error TS17004: Cannot use JSX unless the '--jsx' flag is provided.

Common causes

How to fix it

Set the jsx option

1. Use react-jsx for the modern automatic runtime, or react for classic

{
  "compilerOptions": { "jsx": "react-jsx" }
}

Use the .tsx extension

1. Rename files containing JSX to .tsx

mv src/App.ts src/App.tsx

How to prevent it

• Set jsx in tsconfig and keep JSX in .tsx files so CI compiles components.

Frequently asked questions

Related guides

References

• Node.js documentation
• npm CLI documentation
• GitHub Actions documentation