@orchestrator/gen-io-ts NPM

GenIoTs

Licence

Generate io-ts codecs for classes by decorating props

Installation

$ npm install --save @orchestrator/gen-io-ts

NOTE: Library uses globalThis variable to get Reflect object. You can either provide it manually via provideReflect() function or make sure that Reflect API is loaded globally (via polyfills).

If required - you may need to load globalThis polyfill.

Usage

First decorate your properties that you want to validate:

// my-class.ts

import { Property } from '@orchestrator/gen-io-ts';

class MyClass {
  @Property() // This will validate `prop` to be a string
  prop: string;
  internalProp: any;
}

Now generate codec type for your decorated class:

// main.ts

import { genIoType } from '@orchestrator/gen-io-ts';

import { MyClass } from './my-class.ts';

const myClassType = genIoType(MyClass);

// Then you can validate the type
myClassType.decode({ prop: 'ok' }); // This will produce Right({prop: 'ok'})
myClassType.decode({ prop: false }); // This will produce Left([...])

You can now report any validation errors as usual in io-ts:

import { ThrowReporter } from 'io-ts/lib/ThrowReporter';

ThrowReporter.report(myClassType.decode({...})); // This will throw errors

NOTE: By default every property is optional. To change it - see Required property section.

Advanced usage

Required property

Every property is configured to be NOT required, which means you can assign null/undefined values and validation will not fail.

To change that set isRequired option to true:

import { Property } from '@orchestrator/gen-io-ts';

class MyClass {
  @Property({ isRequired: true }) // Will now fail if `null/undefined` was set
  prop: string;
}

Custom type

Allows to override default inferred type with custom:

import { Property } from '@orchestrator/gen-io-ts';

class MyClass {
  @Property({ type: typeOf(Boolean) }) // Will now allow only booleans instead of strings
  prop: string;
}

Custom type factories

Allows to override/adjust(refine) default type:

import * as t from 'io-ts';
import { Property } from '@orchestrator/gen-io-ts';

class MyClass {
  @Property({
    typeFactory: type => t.refine(type, str => str.length > 0, 'NotEmpty'),
  }) // Will now allow only non empty strings
  prop: string;
}

See: io-ts Refinements for more usage info.

This project was generated with Angular CLI version 7.1.4.