html - Exercise with a loop in javascript

Question

I need for an university exercise to display onscreen with a document.write the tree below using a kind of loop:

I used at the beginning a for loop but i printed only the first row... someone can help me?

This is what I tried:

var numbers = [0, 1, 2, 3, 4] 
for (var i = 0; i <= numbers.length; i++) { 
    if (numbers [i] == 0) { 
        document.write(" * </br>"); 
    } 
    if (numbers [i] == 1) {
        document.write(" *** </br>"); 
    }
    if (numbers [i] == 2) {
        document.write(" ****** </br>"); 
    } 
    if (numbers [i] == 3) {
        document.write(" ******* </br>"); }
    if (numbers [i] == 4) { 
        document.write("********* </br>"); 
    }
    return 
}

Thank You!

Answer 1

I'm going to give you a "golfed-ish" (goldfish? should this be a thing?) version of the code. In other words, the smallest, most obscure code I can think of to accomplish the task. You should not use this, because your teacher will undoubtedly ask you what it means and you won't know, but I'm bored XD

var size = 5;
document.write("<center>"+Array.apply(0,new Array(size)).map(function(_,i) {return new Array((i+1)*2).join(" * ");}).join("<br>")+"</center>");

Demo

As I said, don't use this :p