True Myth

Appearance

True Myth / standard-schema / asyncParserFor

Function: asyncParserFor() ​

asyncParserFor<S>(schema): AsyncParserFor<InferOutput<S>>

Create an asynchronous parser for unknown data to use with any library that implements Standard Schema (Zod, Arktype, Valibot, etc.).

The resulting parser will accept unknown data and emit a Task, which will be Resolved if the schema successfully validates, or Rejected with the Issues generated by the schema for invalid data.

If passed a parser that produces results synchronously, this function will lift it into a Task.

Examples ​

With Zod:

ts
import { asyncParserFor } from 'true-myth/standard-schema';
import * as z from 'zod';

interface Person {
  name?: string | undefined;
  age: number;
}

const parsePerson = asyncParserFor(z.object({
  name: z.optional(z.string()),
  // Define an async refinement so we have something to work with. This is a
  // placeholder for some kind of *real* async validation you might do!
  age: z.number().refine(async (val) => val >= 0),
}));

Other libraries that support async validation or transformation work similarly (but not all libraries support this).

Once you have a parser, you can simply call it with any value and then use the normal Task APIs.

ts
await parsePerson({ name: "Old!", age: 112 }).match({
  Resolved: (person) => {
    console.log(`${person.name ?? "someone"} is ${person.age} years old.`);
  },
  Rejected: (error) => {
    console.error("Something is wrong!", ...error.issues);
  }
});

Type Parameters ​

S ​

S extends StandardSchemaV1<unknown, unknown>

Parameters ​

schema ​

S

A Standard Schema-compatible schema that produces a result, possibly asynchronously.

Returns ​

AsyncParserFor<InferOutput<S>>

A Task that resolves to the output of the schema when it parses successfully and rejects with the StandardSchema FailureResult when it fails to parse.