A type-refinement / validator combinator library for mixed / unknown values in Flow or TypeScript
Refine is a type-refinement / validator combinator library for mixed / unknown values in Flow or TypeScript.
Refine is currently released as @recoiljs/refine on NPM.
Please see the Refine Documentation. To get started learning about Refine, check out the documentation on the core concepts of Utilities and Checkers.
- Refine is useful when your code encounters unknown TypeScript type or mixed Flow type values and you need to assert those values have a specific static type.
- Refine provides an API for building type-refinement helper functions which can validate that an unknown value conforms to an expected type.
- Refine can validate input values and upgrade from previous versions.
Coerce unknown types to a strongly typed variable. assertion() will throw if the input doesn't match the expected type while coercion() will return null.
``jsx
const myObjectChecker = object({
numberProperty: number(),
stringProperty: optional(string()),
arrayProperty: array(number()),
});
const myObjectAssertion = assertion(myObjectChecker);
const myObject: CheckerReturnType
numberProperty: 123,
stringProperty: 'hello',
arrayProperty: [1, 2, 3],
});
`
Using match() and asType() you can upgrade from previous types to the latest version.
`jsx
const myChecker: Checker<{str: string}> = match(
object({str: string()}),
asType(string(), str => ({str: str})),
asType(number(), num => ({str: String(num)})),
);
const obj1: {str: string} = coercion(myChecker({str: 'hello'}));
const obj2: {str: string} = coercion(myChecker('hello'));
const obj3: {str: string} = coercion(myChecker(123));
`
Refine wraps JSON to provide a built-in strongly typed parser.
`jsx
const myParser = jsonParser(array(object({num: number()})));
const result = myParser('[{"num": 1}, {"num": 2}]');
if (result != null) {
// we can now access values in num typesafe way
assert(result[0].num === 1);
} else {
// value failed to match parser spec
}
`
The Recoil Sync library leverages Refine for type refinement, input validation, and upgrading types for backward compatibility. See the recoil-sync` docs for more details.
Refine is currently bundled as part of the Recoil Sync package.
Development of Recoil happens in the open on GitHub, and we are grateful to the community for contributing bugfixes and improvements. Read below to learn how you can take part in improving Recoil.
- Code of Conduct
- Contributing Guide
Recoil is MIT licensed.