R | /mod.ts | ahh@v0.10.1

Idiomatic type-safety functions.

method R.isErr

import { R } from "https://deno.land/x/ahh@v0.10.1/mod.ts";

isErr<T, E extends Error>(res: Result<T, E>): res is Err<E>

Returns whether res is an Err.

Examples

import { R } from "./mod.ts";

console.log(R.isErr(1)); // false
console.log(R.isErr(Error())); // true

E extends Error

res: Result<T, E>

res is Err<E>