JSPM – decoders@2.0.1

Package Exports

decoders
decoders/format
decoders/format.js
decoders/index.js
decoders/index.mjs

This package does not declare an exports field, so the exports above have been automatically detected and optimized by JSPM instead. If any package subpath is missing, it is recommended to post an issue to the original package (decoders) to support the "exports" field. If that is not possible, create a JSPM override to customize the exports field for this package.

Readme

Elegant and battle-tested validation library for type-safe input data for TypeScript and Flow.

Motivation

Data entering your application from the outside world should not be trusted without validation and often is of the any type, effectively disabling your type checker around input values. It's an industry good practice to validate your expectations right at your program's boundaries. This has two benefits: (1) your inputs are getting validated, and (2) you can now statically know for sure the shape of the incoming data. Decoders help solve both of these problems at once.

Example

import { array, iso8601, number, object, optional, string } from 'decoders';

//
// Incoming data at runtime
//
const externalData = {
    id: 123,
    name: 'Alison Roberts',
    createdAt: '1994-01-11T12:26:37.024Z',
    tags: ['foo', 'bar'],
};

//
// Write the decoder (= what you expect the data to look like)
//
const userDecoder = object({
    id: number,
    name: string,
    createdAt: optional(iso8601),
    tags: array(string),
});

//
// Call .verify() on the incoming data
//
const user = userDecoder.verify(externalData);
//    ^^^^
//    TypeScript can automatically infer this type now:
//
//    {
//      id: number;
//      name: string;
//      createdAt?: Date;
//      tags: string[];
//    }
//

Documentation

Documentation can be found on https://decoders.cc.
(Old v1 documentation can still be found here.)