You can create arrays in Typescript quite simply:
let range: number[];
range = [1, 2];
You can do some quite novel things as well, such as to set the object to a range of types:
let range: number[] | string[];
range = [1, 2];
range = ['a', 'b'];
for (let i = 0; i < range.length; i++) {
console.log(range[i].toString());
}
If you want to "cast" the value, you can also do it with an if statement around the item:
for (let i = 0; i < range.length; i++) {
let listVal = range[i];
if (typeof listVal === "number") {
console.log(listVal + 1);
}
}