flow-to-dts

Convert Flow libdefs to Typescript declaration files.

This tool is currently pre-alpha. Contribution of issues, suggesions, and pull requests are welcome!

Usage

Command Line

flow-to-dts input.flow.js output.d.ts

Node API

Transforming a code string:

import { transform } from 'flow-to-dts';

const input = 'type MyCode';

transform(input).then((output) => console.log(output));

Transforming an AST:

import { parse } from '@babel/parser';
import { transformAst } from 'flow-to-dts';

const input = parse('type MyCode');

transformAst(input).then((output) => console.log(JSON.stringify(output)));

Supported Features

(Note that this is not intended as an exhaustive list, but merely a representative sample indicating some of the key transformations performed by the tool.)

| Feature | Supported | Flow | Typescript | |------------------|--------------------|-------------------------------------|---------------------------------------------------| | Flow Header | :heavy_check_mark: | // @flow | // | | Module Exports | :heavy_check_mark: | declare module.exports: MyModule; | export = MyModule; | | Mixed Type | :heavy_check_mark: | mixed | number \| string \| boolean \| symbol \| object | | Nullable Types | :heavy_check_mark: | ?string | string \| null \| undefined | | Tuple Types | :heavy_check_mark: | [number, string] | [number, string] | | Exact Objects | :heavy_check_mark: | {\| name: string \|} | { name: string } | | Open Objects | :heavy_check_mark: | { name: string } | { name: string; [field: string]: any } | | Class Types | :heavy_check_mark: | Class<SomeType> | typeof SomeType | | Built-in Types | :heavy_check_mark: | http$ClientRequest | import { ClientRequest } from "http"; | | Key Types | :x: | $Keys<A> | | | Value Types | :x: | $Values<A> | | | Difference Types | :x: | $Diff<A> | | | Partial Types | :heavy_check_mark: | $Shape<A> | Partial<A> | | Rest Types | :x: | $Rest<A> | | | Supertypes | :x: | $Supertype<A> | | | Subtypes | :x: | $Subtype<A> | | | Existential Type | :heavy_check_mark: | * | any |

Acknowledgements

Special thanks to the creators and maintainers of the following projects that made this tool possible:

• astexplorer
• babel
• babel-handbook
• babel-plugin-tester
• flow-cheatsheet
• flow-typed
• recast
• typescript-vs-flowtype
• yargs