Using Typescript, you can specify an array of type <T> within an object

Question

Having a background in JS, I am currently exploring TS.

My goal is to create an object with a single field, which is an array of strings, while ensuring strong typing.

let container = {
  items: ['Item 1']
}

container.items[0] = 3; // This is incorrect

Although providing an initial value works, what if I want to leave items empty? Here's an example:

let container = {
  items<String>: []
}

container.items.push(3) // This is wrong
container.items.push('abc') // This is correct

Answer 1

Answer №1

Perhaps you just need to adjust the order slightly. Give this a try:

let container = {
  items: [] as string[]
};

Alternatively, consider utilizing an interface as suggested in another response.

Answer 2

Perhaps you just need to adjust the order slightly. Give this a try:

let container = {
  items: [] as string[]
};

Alternatively, consider utilizing an interface as suggested in another response.

Answer 3

One option is to create a custom type.

interface Container {
    items: number[];
}

const container: Container = { items: [] };

Alternatively, if the type is only used once, you can define it inline:

const container: { items: number[] } = { items: [] };

Answer 4

One option is to create a custom type.

interface Container {
    items: number[];
}

const container: Container = { items: [] };

Alternatively, if the type is only used once, you can define it inline:

const container: { items: number[] } = { items: [] };