Create strongly typed array of arrays in TypeScript

You do it exactly like in Java/C#, e.g. (in a class):

class SomeClass {
    public someVariable: Array<Array<AnyTypeYouWant>>;
}

Or as a standalone variable:

var someOtherVariable: Array<Array<AnyTypeYouWant>>;

int is not a type in TypeScript. You probably want to use number:

var listOfLists : number[][];