Creating an Isoceles Triangle in Javascript with Methods and For Loops

I am working on a Javascript question from a book to build an Isoceles Triangle from methods and a for loop. The question requires that you build two methods first and then use those to create the triangle. I have the below, but it seems to be ignoring these lines:

spaces = spaces – 1;
stars = stars + 2;
because when I run it, I only get 5 lines of 3 spaces and then one asterisk.

Any help is appreciated. Thank you.

import java.util.Scanner;
class Main {
  public static void main(String[] args) {
    Scanner input = new Scanner(System.in);
    int size;
    System.out.print("What size is the triangle? ");
    size = input.nextInt();
    drawIsoTriangle(size);
   }
   public static void displaydrawBar(int length) {
    for (int i = 0; i < length; i++) {
    System.out.print("*");
    }
   }
   public static void displaydrawBar(int length, String mark) {
    for (int i = 0; i < length; i++) {
    System.out.print(mark);
    }
   }
   public static void drawIsoTriangle(int size) {
    for (int i = 0; i < size; i++) {
      int spaces = size - 1;
      int stars = 1;
      displaydrawBar(spaces, " ");
      displaydrawBar(stars);
      System.out.println();
      spaces = spaces - 1;
      stars = stars + 2;
    } 
   } 
}