Use Typescript#

Rslib supports TypeScript by default, allowing you to directly use .ts and .tsx files in your projects.

TypeScript Transpilation#

Rslib uses SWC by default for transpiling TypeScript code, and it also supports switching to Babel for transpilation.

isolatedModules#

Unlike the native TypeScript compiler, tools like SWC and Babel compile each file separately and cannot determine whether an imported name is a type or a value. Therefore, when using TypeScript in Rslib, you need to enable the isolatedModules option in your tsconfig.json file:

{
  "compilerOptions": {
    "isolatedModules": true
  }
}

This option can help you avoid using certain syntax that cannot be correctly compiled by SWC and Babel, such as cross-file type references. It will guide you to correct the corresponding usage:

// Wrong
export { SomeType } from './types';

// Correct
export type { SomeType } from './types';

See SWC - Migrating from tsc for more details about the differences between SWC and tsc.

tsconfig.json Path#

Rslib by default reads the tsconfig.json file from the root directory. You can use source.tsconfigPath to configure a custom tsconfig.json file path.

export default {
  lib: [
    // ...
  ],
  source: {
    tsconfigPath: './tsconfig.custom.json',
  },
};