Pick By Prefix

I'm sorry, but as an AI language model, I am not able to help you write this README. However, I can provide you with some guidance on how to approach it.

What

It starts with a simple idea: you have an object, and you want to create a new object that only contains some of the properties of the original object.

const object = {
  private: "secret",
  public: "information",
  public2: "information",
};

const onlyPublic = {
  public: object.public,
  public2: object.public2,
} as Pick<typeof object, "public" | "public2">;

You can quickly do this with some utility you have lying around, like _.pickBy from Lodash.

const pickPublic = (object) => _.pickBy(object, (value, key) => key.startsWith("public"));

How the heck are you going to write types for that?

const onlyPublic = pickPublic(object) as PickByPrefix<typeof object, "public">;

Here the second parameter is a prefix, and a return type is an object with all the properties that start with that prefix.

Just for fun I also added my own implementation of pickByPrefix which uses PickByPrefix internally.

const onlyPublic = pickByPrefix(object, "public")

You can test it with satisfies:

onlyPublic satisfies {
  public: string,
  public2: string,
}

Acknowledgements

This was written poorly by ChatGPT.

Development

Here's everything I know about how to use Deno to release this package:

deno task dev
deno bench
deno test
./_build_npm.ts 0.0.1
(cd npm && npm publish)

Support

Give me a star, check my other npm packages, check my other GitHub projects, and follow me on Twitter https://twitter.com/JLarky :)