Created
December 10, 2023 10:52
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TypeScript Monad function
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| interface IMonad<T> { | |
| andThen: <U>(fn: (value: T, finish: () => void) => U) => IMonad<U>; | |
| } | |
| export const Monad = <T>(initial: T, finished = false): IMonad<T> => { | |
| if (finished) { | |
| return { | |
| andThen: <U>(_: (_: T, _: () => void) => U) => { | |
| return Monad(null, true); | |
| }, | |
| } as IMonad<T>; | |
| } | |
| return { | |
| andThen: <U>(f: (value: T, finish: () => void) => U) => { | |
| let inner = false; | |
| const result = f(initial, () => { | |
| inner = true; | |
| }); | |
| if (inner) { | |
| return Monad(result, true); | |
| } | |
| return Monad(result); | |
| }, | |
| } as IMonad<T>; | |
| }; | |
| const x = Monad(1); | |
| x.andThen((x) => x + 1) | |
| .andThen((x) => x.toString()) | |
| .andThen((x, finish) => { | |
| if (x === '2') { | |
| finish(); | |
| } | |
| }) | |
| .andThen(() => console.log('hii')); // Never gets executed |
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Supports async/await too