Babel plugin to convert Flow code into TypeScript
$ npm install -g @babel/cli @babel/core
$ npm install babel-plugin-flow-to-typescript
# you must use babel@^7.x.x
$ babel --version
7.4.4 (@babel/core 7.4.5)
$ babel --plugins babel-plugin-flow-to-typescript ${SRC_FLOW_FILE} -o ${DEST_TS_FILE}| 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 |
unknown |
| ✅ | 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] |
| ✅ | $Shape | $Shape<T> |
Partial<T> |
| ✅ | Class | Class<T> |
typeof T |
| ✅ | typeof operator | typeof foo |
typeof foo |
| ✅ | JSX | - | - |
| ✅ | Tuple type | [number, string] |
[number, string] |
| ✅ | Type alias | type A = string |
type A = string |
| ✅ | Flow Ignore | $FlowFixMe |
any |
| ✅ | Interfaces | interface X { +prop: string } |
interface X { readonly prop: string } |
| ✅ | Optional Members | a?.b |
... |
| ✅ | Declare functions | declare function x(false): true; |
function x(x0: false): true; |
| ✅ | Declare Class | ... |
... |