Create union of unique array items from union of types (typescript)

Issue

I'd like to ask, is it possible to declare an array of unique types from union of those types?

I have this type Value:

type Value = string | number

Then I created type Values like this:

type Values = Value[]

but that creates a type:

type Values = (string|number)[]

but how can I achieve this from the type Value?

type Values = string[] | number[]

Because basically I have a function that renders checkbox-es for table filters. That checkbox will always have either string or number as a value.

Then when you click on a checkbox, it adds that value to an array. For example, you have a column firstName and you add two names to that filter. It then becomes an array of string or array of number: string[] | number[] which would represent my type Values.

So is there a way to create type Values from type Value?

I created this sample sandbox just to compare those types.

Thanks for any input!

Solution

I would choose of restricted templating

type Values<T extends string | number> = T[];

const myArr: Values<string> = [
    'foo',
    'bar',
];

const myArr2: Values<number> = [
    1,
    2,
];

---

Or use overloaded types (let typescript decide the type depending on what's inside of the array)

type ValueTypeA = string[];
type ValueTypeB = number[];

type Values = ValueTypeA | ValueTypeB;

const myArr: Values = [
    'foo',
    'bar',
];

const myArr2: Values = [
    1,
    2,
];

Answered By - Orelsanpls