Typesafe combinatorial data validators/parsers for typescript using fp-ts.
Documentation is available here.
npm install ununknownThe crux of the problem this library solves is the following:
How do we ensure that an object of type unknown is actually
of type T in our typescript project? This problem comes up
in several situations, including, if not limited to:
- REST APIs
- Javascript Interop
- JSON RPCs
import { array, field, isSuccess, object, Parser, recursive, runParser, runParserEx, thing } from "../src";
interface Person {
name: {
first: string;
last: string;
};
age?: number;
children: Array<Person>;
}
const personValidator: Parser<Person, unknown> = recursive(() =>
object.of({
name: field.required(
"name",
object.of({
first: field.required("first", thing.is.string),
last: field.required("last", thing.is.string)
})
),
age: field.optional("age", thing.is.number),
children: field.required("children", array.of(personValidator))
})
);
// Check if validation succeeded
const test = {
name: {
first: "Kaden",
last: "Thomas"
},
age: 20,
children: []
};
// Throws an error with result.left if it fails
const result: Person = runParserEx(personValidator, test);
// Non-exception based
const parseResult = runParser(personValidator, test);
if (isSuccess(parseResult)) {
const o: Person = parseResult.right;
console.log("succeeded");
} else {
console.log("failed with error: ", parseResult.left);
}- Circular references are not handled, which should not affect anything encoded in JSON. However, this is a valid validation case and will be handled in the future.