mapErr | /mod.ts | pazza@v0.3.0

Parser combinators library designed for Deno, but also works on browsers and Node.js.

function mapErr

import { mapErr } from "https://deno.land/x/pazza@v0.3.0/mod.ts";

mapErr<T, E1, E2, I extends Input, CtxIn, CtxOut>(parser: IParser<T, E1, I, CtxIn, CtxOut>, fn: (error: E1) => E2): IParser<T, E2, I, CtxIn, CtxOut>

Execute the embedded parser. If it fails, apply provided function on the error.

const parser = map(digit(), error => "Not a digit.");
parser("a").error === "Not a digit.";

Type Parameters

I extends Input

CtxIn

CtxOut

embededd parser

fn: (error: E1) => E2

function to be applied on error