Magic-type NPM

Installation

With Yarn

yarn global add magic-type

With NPM

npm install -g magic-type

You could also use Magic Type locally as well.

Usage

Let's take the following code as an example.

// typings/api.ts
export type MyAPIRequest = {
  time: number;
  input: string;
};

Compile TypeScript definitions

Usage: magictype [options]

Options:
  -V, --version          output the version number
  -i --inputFile <file>  The entrypoint of files to be compiled
  -o --outputDir <dir>   The output directory of compiled files
  -c --cjs               Transpile modules to CommonJS (Otherwise it will output ES modules)
  -h, --help             output usage information

Use magic types at runtime

import { MyAPIRequest } from "./api";

// Use Magic Types as normal TypeScript types
type MyType = {
  key: MyAPIRequest;
};

// Use Magic Type at Runtime

// Check if user input matches MyAPIRequest
function checkMyInput(input: any) {
  return MyAPIRequest.validate(input);
}

// Format user input to match MyAPIRequest
function formatMyInput(input: any) {
  return MyAPIRequest.format(input);
}

// Generate a mock MyAPIRequest data
function getMockData() {
  return MyAPIRequest.deriveLiteral([]).mock();
}

Developer Experience with TypeScript's type guard
Runtime Screenshot:

Unsupported Syntax

Please be noted there's no warnings against unsupported syntax yet (And Magic Type may crash as well). Please kindly check by yourself.

extends keyword in interface declaration will be ignored.
Union (A | B) and intersection(A & B) on index signatures are not supported.
Functions
infer keyword
ReturnType<T> and InstanceType<T> are not supported due to unsupported infer keyword and functions.