see if tassign is still relevant with later typescript versions

[SethDavenport]

object spread is supported now; check out how its typings work. If it makes sense, adjust the 'strongly typed reducers' article

[SethDavenport]

potentially deprecate tassign if that makes sense too

[e-schultz]

Quickly playing around in the TypeScript repl...

interface State {
  name: string;
  age: number;
  nickName: string;
}

let reducer = (state: State, action): State => {
  switch (action.type) {
    case 'ONE':
      return { ...state, x: 'y' }; // isn't an error - objects returned by spread don't care about extra params
    default:
      return state;
  }
  
}

interface State {
  name: string;
  age: number;
  nickName: string;
}

let reducer = (state: State, action): State => {
  switch (action.type) {
    case 'ONE':
        return { x: 'hi', name: '', age: 0, nickName: 'bob' } // this would complain due to 'x'  not being on State
    default:
      return state;
  }
  
}

Some discussion around this in the TypeScript repo - #10727 - and some design notes around this behaviour is in Design Meeting Notes, 12/16/2016

There is also an issue for Exact Types which is in proposal that seems like it'd solve this.

Someone linked to spread operations with exact types - guide is geared towards react-redux, but demos using Partial's .

but the tl;dr I guess - until the Exact proposal gets implemented - still value in tassign.

[SethDavenport]

OK cool