Implementing Stacks & Queues

class Stack {
  constructor() {
    this.minStack = [];
    this.mainStack = [];
  }
  
  push(element) {
    this.mainStack.push(element);
    if (!this.minStack.length || element <= this.minStack[this.minStack.length - 1]) {
      this.minStack.push(element);
    }
  }
  
  pop() {
    if (this.mainStack.pop() === this.minStack[this.minStack.length - 1]) {
      this.minStack.pop();
    }
  }
  
  getMin() {
    return this.minStack[this.minStack.length - 1];
  }
}