Last active
March 23, 2023 01:48
-
-
Save turbotobias/8fb8c324a63beb4bcfc66e30e42892a4 to your computer and use it in GitHub Desktop.
Rust Result in Typescript
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| export type Result<T, E = undefined> = { ok: true; value: T } | { ok: false; error: E | undefined } | |
| export const Ok = <T>(data: T): Result<T, never> => ({ ok: true, value: data }) | |
| export const Err = <E>(error?: E): Result<never, E> => ({ ok: false, error }) |
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| import { type Result, Ok, Err } from "./@result" | |
| const truthy = (arg?: any) => (!!arg ? Ok(arg) : Err(`falsy`)) | |
| const truth = truthy("something") | |
| truth.ok ? console.log(`truthy`) : truth.error ? console.trace(`falsy ${truth.error}`) : console.trace(`unknown error`) |
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| import { type Result, Ok, Err } from "./@result" | |
| const numberIsLessThan10 = (num: number): Result<number, string> => { | |
| if (num < 10) return Ok(num) | |
| return Err("number is not less than 10") | |
| } | |
| const number = numberIsLessThan10(5) | |
| if (number.ok) useNumber(number.value) // valid | |
| else if (number.error) console.trace(number.error) // invalid with known error | |
| else console.trace("unknown error") // invalid with unknown error |
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| import { type Result, Ok, Err } from "./@result" | |
| const fetchGeoJson = async (): Promise<Result<GeoJson, string>> => { | |
| const res = await fetch(`/api`) | |
| const json = await res.json() | |
| if (!json) return Err("could not get json from api") | |
| if (!validate(json.geo)) return Err("did not get valid geo json from api") | |
| return Ok(json.geo) | |
| } | |
| const geoJson = await fetchGeoJson() | |
| if (geoJson.ok) useGeoJson(geoJson.value) // valid | |
| else if (geoJson.error) console.trace(geoJson.error) // invalid with known error | |
| else console.trace("unknown error") // invalid with unknown error |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment