how to limit array's type in specific order in typescript

Question

how to limit array's type in specific order in typescript instead of defining paradigm.

that means, in ts, we just declare a array definition like:

const arr:Array<any> = []

I want get a specific order in definition array,like:

const arr = ['string', 0, ...];

value can only be string tyoe at position 0, and can only be number type at position 1...

thanks

The arrays at Typescript are homogenous, so what you say can not be done. You can use an object for this purpose. — botika, Apr 24 '18 at 02:51
I refered to prosemirror-model's definition, it used like this, thank you — yungcho, Apr 24 '18 at 02:55

score 3 · Accepted Answer · answered Apr 24 '18 at 05:58

If you want to limit the size to 2 elements you can achieve this with a tuple

const myTuple: [string, number] = ['test', 3]

or extracted the tuple type definition into a type

type myTupleType = [string, number]
const myTuple2: myTupleType = ['test', 3]

score 1 · Answer 2 · answered Apr 24 '18 at 03:04

1

It can be done with intersection type:

type OrderedArray<T> = Array<T> & {
    0?: string;
    1?: number;
}

const arr: OrderedArray<any> = ['string', 0, ...];

answered Apr 24 '18 at 03:04

Estus Flask

2 Answers2