README.md

babel-plugin-flow-to-typescript

Babel plugin to convert Flow code into TypeScript

How to use

$ yarn global add @babel/cli
$ yarn add @steelbrain/babel-plugin-flow-to-typescript

# you must use babel@^7.x.x
$ babel --version
7.0.0-beta.44 (@babel/core 7.0.0-beta.44)

$ babel --plugins @steelbrain/babel-plugin-flow-to-typescript ${SRC_FLOW_FILE} -o ${DEST_TS_FILE}

Implementation status

Supported?	Syntax	Flow	TypeScript
✅	Maybe type	let a:?number	let a: number | null | undefined
✅	Void type	void	void
✅	Object type	Object	object
✅	Mixed type	mixed	{}
✅	Function type	(A, B) => C	(x1: A, x2: B) => C
✅	Exact type	{| a: A |}	{ a: A }
✅	Indexers	{ [A]: B }	{ [a: A]: B }
✅	Existential type	Map<*, *>	Map<any, any>
✅	Opaque types	opaque type A = B	type A = B
✅	Variance	interface A { +b: B, -c: C }	interface A { readonly b: B, c: C }
✅	Type parameter bounds	function f<A: string>(a:A){}	function f<A extends string>(a:A){}
✅	Cast	(a: A)	(a as A)
✅	type/typeof import	import type A from 'module'	import A from 'module'
✅	$Keys	$Keys<X>	keyof X
✅	$Values	$Values<X>	X[keyof X]
✅	$ReadOnly	$Readonly<X>	Readonly<X>
✅	$Exact	$Exact<X>	X
✅	$Diff	$Diff<X, Y>	Pick<X, Exclude<keyof X, keyof Y>>
✅	$PropertyType	$PropertyType<T, k>	T[k]
✅	$ElementType	$ElementType<T, k>	T[k]
✅	typeof operator	typeof foo	typeof foo
✅	JSX	-	-
✅	Tuple type	[number, string]	[number, string]
✅	Exact type	`{	a: T
✅	Type alias	type A = string	type A = string
✅	Flow Ignore	$FlowFixMe	any