npm package discovery and stats viewer.

Discover Tips

  • General search

    [free text search, go nuts!]

  • Package details

    pkg:[package-name]

  • User packages

    @[username]

Sponsor

Optimize Toolset

I’ve always been into building performant and accessible sites, but lately I’ve been taking it extremely seriously. So much so that I’ve been building a tool to help me optimize and monitor the sites that I build to make sure that I’m making an attempt to offer the best experience to those who visit them. If you’re into performant, accessible and SEO friendly sites, you might like it too! You can check it out at Optimize Toolset.

About

Hi, 👋, I’m Ryan Hefner  and I built this site for me, and you! The goal of this site was to provide an easy way for me to check the stats on my npm packages, both for prioritizing issues and updates, and to give me a little kick in the pants to keep up on stuff.

As I was building it, I realized that I was actually using the tool to build the tool, and figured I might as well put this out there and hopefully others will find it to be a fast and useful way to search and browse npm packages as I have.

If you’re interested in other things I’m working on, follow me on Twitter or check out the open source projects I’ve been publishing on GitHub.

I am also working on a Twitter bot for this site to tweet the most popular, newest, random packages from npm. Please follow that account now and it will start sending out packages soon–ish.

Open Software & Tools

This site wouldn’t be possible without the immense generosity and tireless efforts from the people who make contributions to the world and share their work via open source initiatives. Thank you 🙏

© 2024 – Pkg Stats / Ryan Hefner

@tsmirror/reflect

v0.0.3

Published

Typescript runtime inspection

Downloads

13

Readme

@tsmirror/reflect

A Typescript transformer to include compiler types into the compiled code.

Requirement

TypeScript >= 2.4.1

How to use this package

This package is a type script transformer.

Why ?

Typescript alread has some support for metadata reflection at https://www.typescriptlang.org/docs/handbook/decorators.html#metadata but :

  1. It is tightly linked to decorators, preventing its usage with a free floating function
  2. It serialize Typescript's types in a way that loose a lot of information (everything is Object)

This package instead emits as much information as possible in a serializable format.

Here is a list of some cool usage for the ReflectType object.

  • Casting and checking: you can use the ReflectType to validate user input.
  • Tokenless Dependency Injection: see the @tsmirror/di package
  • Configurationless Fuzz-testing: see the @tsmirror/fuzzer package
  • Graphql générations from function's types: see the @tsmirror/graphql package

How to use reflect

import { reflect, ReflectType } from '@tsmirror/reflect';

interface MyInterface {
  id: string;
  name: string;
  age: number;
}

let value : MyInterface = {id: '1', name: 'hello', age: 42}

const myinterfaceType: ReflectType = reflect<MyInterface>();
// or
const myinterfaceType: ReflectType = reflect(value);

console.log(myinterfaceType);
/* {
    kind: "interface",
    name: 'MyInterface',
    members: [
        { name: "id", type: { kind: "string" } },
        { name: "name", type: { kind: "string" } },
        { name: "age", type: { kind: "number" } },
    ]
} */

How to use reflected/getTypeOf

The reflect function can only be called at a spot where the typescript compiler knows the type of the object, so this wont work :

function logType(arg: any) {
  console.log(reflect(arg)); // will only log {kind: Any}
}

logType(value);

To sidestep this issue, you can use the reflected/getTypeOf combo

import { reflected, getTypeOf } from "@tsmirror/reflect";
import "reflect-metadata";

value = reflected(value);

function logType(arg: any) {
  console.log(getTypeOf(arg)); // full ReflectType
}

logType(value);

The reflect type will be stored in the object's metadata using the reflect-metadata package.

How to use the reflecting function

While more hacky, the reflecting function allows a package to expose a clean API to their user. It is used in all other packages from the @tsmirror organisation.


const _logType = (rtype: ReflectType) => (arg: any) => console.log(arg, 'has type', rtype)
const logType = reflecting(_logType) // logType: Reflecting<(arg: any) => void>

logType(value)
/* {id: '1', name: 'hello', age: 42} has type {
    kind: "interface",
    name: 'MyInterface',
    members: [...] } */

How to use the custom transformer

Unfortunately, TypeScript itself does not currently provide any easy way to use custom transformers (See https://github.com/Microsoft/TypeScript/issues/14419).

See [https://github.com/madou/typescript-transformer-handbook/#consuming-transformers](Madou's transformer handbook) for how you can use them with various compilers and bundlers.

Note

  • The reflect function will only be compiled out as a call expression. ie. reflect.toString() will output the stub function's definition.

License

MIT