How to call a static method in javascript from a string name? [duplicate]

I have a class lets say a test1 that has static methods #a and #b and is called from a public method lets say message(methodName) that has the argument, methodName (either a or b) that decided which method to call. If a and be were not static, I could do this

class test1 {
    message(methodName) {
    this[methodName]
    }
    a() {
    }
    b() {
    }
}

but because they are static, I wanted to do,

    class test1 {
    message(methodName) {
    this["#"+methodName]
    }
    #a() {
    }
    #b() {
    }
}

But it does not work. Am i doing something wrong or is there some other way??