// Union of primitives, number, arrays, and C1
let var1: number | "hello" | "world" | true | false | number[] | string[];

if (var1.constructor === Number) {
    var1; // number
}

if (var1.constructor === String) {
    var1; // "hello" | "world"
}

if (var1.constructor === Boolean) {
    var1; // boolean
}

if (var1.constructor === Array) {
    var1; // number[] | string[]
}