pragmatic-fp-ts/deno_lib/tryCatch.ts

Opinionated functional programming library with easy use in mind

import { Mappable } from "./main.ts";

type Catcher<A, B> = ((err: Error, value: A) => B) | ((err: Error) => B);

export function tryCatch<A, B>(tryer: Mappable<A, B>, catcher: Catcher<A, B>, value: A): B;
export function tryCatch<A, B>(tryer: Mappable<A, B>, catcher: Catcher<A, B>): (value: A) => B;
export function tryCatch<A, B>(tryer: Mappable<A, B>): (catcher: Catcher<A, B>) => (value: A) => B;
export function tryCatch<A, B>(tryer: Mappable<A, B>, catcher?: Catcher<A, B>, value?: A) {
  if (arguments.length === 1) {
    return function (c: Catcher<A, B>, v?: A) {
      return arguments.length === 1 ? tryCatch(tryer, c) : tryCatch(tryer, c, v!);
    };
  } else if (arguments.length === 2) {
    return (v: A) => tryCatch(tryer, catcher!, v);
  }

  try {
    return tryer(value!);
  } catch (err) {
    if (!catcher) {
      throw new Error("No catcher fn defined");
    } else {
      return catcher(err as Error, value as any);
    }
  }
}