import { decoder } from "https://deno.land/x/fun@v2.0.0/mod.ts";
const { fromPredicate } = decoder;
Construct a Decoder<A, A> from a Predicate and a reason for failure or a Decoder<A, B> from a Refinement<A, B> and a reason for failure. While decoding, the value A is passed to the predicate/refinement. If it returns true then the result is wrapped in Success, otherwise the value and reason are wrapped in Failure.
Examples
Example 1
Example 1
import * as D from "./decoder.ts";
import * as R from "./refinement.ts";
import { pipe } from "./fn.ts";
const nonEmpty = D.fromPredicate(
(s: string) => s.length > 0, // Predicate
"noninit string"
);
const string = D.fromPredicate(R.string, "string");
const nonEmptyString = pipe(
string,
D.compose(nonEmpty),
);
const result1 = nonEmptyString(null); // Left(DecodeError)
const result2 = nonEmptyString(""); // Left(DecodeError)
const result3 = nonEmptyString("Hello"); // Right("Hello")
Type Parameters
A extends B