Get keys of a Typescript interface as array of strings

Question

I've a lot of tables in Lovefield and their respective Interfaces for what columns they have.

Example:

export interface IMyTable {
  id: number;
  title: string;
  createdAt: Date;
  isDeleted: boolean;
}

I'd like to have the property names of this interface in an array like this:

const IMyTable = ["id", "title", "createdAt", "isDeleted"];

I cannot make an object/array based on the interface IMyTable directly which should do the trick because I'd be getting the interface names of the tables dynamically. Hence I need to iterate over these properties in the interface and get an array out of it.

How do I achieve this result?

Answer 1

As of TypeScript 2.3 (or should I say 2.4, as in 2.3 this feature contains a bug which has been fixed in [email protected]), you can create a custom transformer to achieve what you want to do.

Actually, I have already created such a custom transformer, which enables the following.

https://github.com/kimamula/ts-transformer-keys

import { keys } from 'ts-transformer-keys';

interface Props {
  id: string;
  name: string;
  age: number;
}
const keysOfProps = keys<Props>();

console.log(keysOfProps); // ['id', 'name', 'age']

Unfortunately, custom transformers are currently not so easy to use. You have to use them with the TypeScript transformation API instead of executing tsc command. There is an issue requesting a plugin support for custom transformers.