javascript - Iterate over interface properties in TypeScript

Question

I need to map interface properties to objects:

interface Activity {
  id: string,
  title: string,
  body: string,
  json: Object
}

I currently do:

headers: Array<Object> = [
  { text: 'id', value: 'id' },
  { text: 'title', value: 'title' },
  { text: 'body', value: 'body' },
  { text: 'json', value: 'json' }
]

This gets very repetitive. What I would like is something like this:

headers: Array<Object> = Activity.keys.map(key => {
  return { text: key, value: key }
})

Answer 1

You can't, interfaces are only for compile time because javascript doesn't support it.

What you can do is something like:

const Activity = {
    id: "",
    title: "",
    body: "",
    json: {}
}

type Activity = typeof Activity;
const headers: Array<Object> = Object.keys(Activity).map(key => {
    return { text: key, value: key }
});

(code in playground)