target

{
  target: '19' // or '18', '17'
}

• Reference
  • target
• Usage
  • Targeting React 19 (default)
  • Targeting React 17 or 18
• Troubleshooting
  • Runtime errors about missing compiler runtime
  • Runtime package not working
  • Checking compiled output

Reference

target

Configures the React version compatibility for the compiled output.

Type

'17' | '18' | '19'

Default value

'19'

Valid values

• '19': Target React 19 (default). No additional runtime required.
• '18': Target React 18. Requires react-compiler-runtime package.
• '17': Target React 17. Requires react-compiler-runtime package.

Caveats

• Always use string values, not numbers (e.g., '17' not 17)
• Don’t include patch versions (e.g., use '18' not '18.2.0')
• React 19 includes built-in compiler runtime APIs
• React 17 and 18 require installing react-compiler-runtime@rc

Usage

Targeting React 19 (default)

For React 19, no special configuration is needed:

{
  // defaults to target: '19'
}

The compiler will use React 19’s built-in runtime APIs:

// Compiled output uses React 19's native APIs
import { c as _c } from 'react/compiler-runtime';

Targeting React 17 or 18

For React 17 and React 18 projects, you need two steps:

1. Install the runtime package:

npm install react-compiler-runtime@rc

2. Configure the target:

// For React 18
{
  target: '18'
}

// For React 17
{
  target: '17'
}

The compiler will use the polyfill runtime for both versions:

// Compiled output uses the polyfill
import { c as _c } from 'react-compiler-runtime';

Troubleshooting

Runtime errors about missing compiler runtime

If you see errors like “Cannot find module ‘react/compiler-runtime’“:

1. Check your React version:

   npm why react

2. If using React 17 or 18, install the runtime:

   npm install react-compiler-runtime@rc

3. Ensure your target matches your React version:

   {
     target: '18' // Must match your React major version
   }

Runtime package not working

Ensure the runtime package is:

1. Installed in your project (not globally)
2. Listed in your package.json dependencies
3. The correct version (@rc tag)
4. Not in devDependencies (it’s needed at runtime)

Checking compiled output

To verify the correct runtime is being used, note the different import (react/compiler-runtime for builtin, react-compiler-runtime standalone package for 17/18):

// For React 19 (built-in runtime)
import { c } from 'react/compiler-runtime'
//                      ^

// For React 17/18 (polyfill runtime)
import { c } from 'react-compiler-runtime'
//                      ^