Extract a key/value object type from the properties of an array of objects in Typescript

Question

I have a constant array of objects that use the same properties. Something like this:

const allData = [{
  name: 'info', content: Info
},{
  name: 'other', content: Other
},{
  ...
}];

Now I want to create a variable that after some other code is run, will map these into an object where the keys are the strings of the name property and the values are instances of the content property. Given that, I want to know how I can define such a type in Typescript that would basically extract those properties from my constant so that it becomes like this in the end:

Type ContentInstances = {
  info: Info,
  other: Other 
  ...
}

Is there such a way using typeof and other things on Typescript to achieve this dynamically based on allData constant?

EDIT Basically at a later stage, I will have something like this:

let myVar: ContentInstances;
...
myVar = allData.reduce((obj, value) => {
  obj[value.name] = new value.content(customParam);
  return obj;
}, {})

Answer 1

The following should do the trick:

const allData = [
  {
    name: "info",
    content: { hey: "you" },
  },
  {
    name: "other",
    content: { bro: "chill" },
  },
] as const;

type ContentInstances = {
  [K in typeof allData[number]["name"]]: Extract<
    typeof allData[number],
    { name: K }
  >["content"];
};

declare const foo: ContentInstances;

foo.info.hey;
foo.other.bro;

The type ContentInstances iterates through all the "name" keys of the objects contained into allData. It maps each key into the union of the objects having that key, to then indexing the union with the "content" key.