Create custom type for an array

Question

I am using Typescript with Redux and want to put a type for initial state.

Examples I have seen assume initial state is key value pairs like:

const INITIAL_STATE: State = {
    id: '1',
    firstName: 'Michael',
    lastName: 'Black',
  }

where the type is defined as

export interface State {
  id: string
  firstName: string
  lastName: string
}

How about if the type is defined as

const INITIAL_STATE: State = [
  {
    id: '1',
    firstName: 'Michael',
    lastName: 'Black',
  },
  {
    id: '2',
    firstName: 'Tony',
    lastName: 'Montana',
  }
]

How would the type definition look? I did try look for answer as it looks like it should be simple to do but couldn't find anything...

Edit:

I guess I could do

const INITIAL_STATE: Array<State> = [
  {
    id: '1',
    firstName: 'Michael',
    lastName: 'Black',
  },
  {
    id: '2',
    firstName: 'Tony',
    lastName: 'Montana',
  }
]

But how about if I wanted a new definition, CustomerState?

Something like

export interface CustomerState Array<State>

which is a syntax error of course.

Um Array<State> or State [] ?

Titian Cernicova-Dragomir
– Titian Cernicova-Dragomir

2019-05-07 01:10:10 +00:00
Commented May 7, 2019 at 1:10 — Titian Cernicova-Dragomir
– Titian Cernicova-Dragomir, Commented May 7, 2019 at 1:10
Tried..'export interface CustomerState Array<State>'

alif
– alif

2019-05-07 01:11:26 +00:00
Commented May 7, 2019 at 1:11 — alif
– alif, Commented May 7, 2019 at 1:11
i think i know the problem. see update

alif
– alif

2019-05-07 01:13:37 +00:00
Commented May 7, 2019 at 1:13 — alif
– alif, Commented May 7, 2019 at 1:13

basarat · Accepted Answer · 2019-05-07 01:16:19Z

2

export interface CustomerState Array

I would

export interface Person {
  id: string
  firstName: string
  lastName: string
}
export type State = Person[];
const INITIAL_STATE: State = [
  {
    id: '1',
    firstName: 'Michael',
    lastName: 'Black',
  },
  {
    id: '2',
    firstName: 'Tony',
    lastName: 'Montana',
  }
]

answered May 7, 2019 at 1:16

basarat

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