#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.

#Preset types

@rslib/core provides some preset type definitions, including CSS Modules, static assets, import.meta and other types.

You can create a src/env.d.ts file to reference it:

/// <reference types="@rslib/core/types" />

#Type checking

When transpiling TypeScript code using tools like SWC and Babel, type checking is not performed.

Rslib provides the lib.dts configuration item for generating TypeScript declaration files, and type checking is performed by default during the generation process.

You can skip type checking by setting the noCheck configuration item to true in the tsconfig.json file.

#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',
  },
};

#Decorators version

By default, Rslib uses the 2022-03 version of the decorators.

If experimentalDecorators is enabled in tsconfig.json, Rslib will set source.decorators.version to legacy to use the legacy decorators.