babel-plugin-flow-to-typescript

Babel plugin to convert Flow code into TypeScript

How to use

$ 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}

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 | 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 | ... | ... |