ts2fable

0.7.1 verified Fri May 01 auth: no javascript

A TypeScript definition file parser for the Fable compiler, converting TypeScript type definitions (.d.ts) into F# (.fs) files for use in Fable projects. Current stable version is 0.7.1, with releases on a quarterly to biannual cadence. It handles TypeScript modules, types, and interfaces, generating idiomatic F# bindings with support for generics, callbacks, and unions. Key differentiators: integrates with Fable's type system, supports modern TypeScript features, and includes a command-line interface for batch processing.

Common errors

error Error: undefined is not iterable ↓

cause Bug in ts2fable 0.7.0 when parsing certain TypeScript files with nested constructs.

fix

Update to ts2fable 0.7.1 or later.

error Option has no value ↓

cause Missing required command-line argument or incorrect input file path.

fix

Ensure the input .d.ts file exists and is accessible; use --help to check required arguments.

error Cannot find module 'typescript' ↓

cause The typescript peer dependency is not installed.

fix

Run npm install typescript in the same directory where ts2fable is installed.

Warnings

breaking Version 0.7.0 removed the Yargs dependency and changed some command-line options. ↓

fix Use new CLI arguments; check --help for updated options.

breaking Version 0.6.0 introduced Fable.Core 3.0 support, breaking compatibility with Fable.Core 2.x generated bindings. ↓

fix Regenerate bindings with ts2fable 0.6.0 or later, and update Fable.Core dependency.

deprecated The global installation via -g is deprecated; prefer using npx to ensure you use the latest version. ↓

fix Use `npx ts2fable` instead of global install.

gotcha Error: undefined is not iterable - occurs with some V8 TypeScript definitions. ↓

fix Upgrade to 0.7.1 which fixes issue #334.

gotcha Generated F# modules may have incorrect PascalCase naming if the TypeScript module name contains uppercase letters like 'BABYLON'. ↓

fix Upgrade to 0.7.0 or later which fixes this naming issue (#299).

Install

npm install ts2fable

yarn add ts2fable

pnpm add ts2fable

Imports

ts2fable
wrong
```
npm install ts2fable
```
correct
```
npm install -g ts2fable
```
ts2fable is typically installed globally as a CLI tool; local install is possible but not recommended.
default
wrong
```
ts2fable input.d.ts > output.fs
```
correct
```
npx ts2fable input.d.ts output.fs
```
Use npx for execution; piping to a file may cause issues with error handling.
CLI usage
```
ts2fable --help
```
No import needed; the package is used as a CLI tool, not a library.

Quickstart

Generates F# bindings for lodash from its TypeScript definitions using the current version of ts2fable.

npx ts2fable https://raw.githubusercontent.com/DefinitelyTyped/DefinitelyTyped/master/types/lodash/index.d.ts lodash.fs