title: Why does my last customer entry override the previous entry instead of adding it to the customer object? JS
body: <p>Why does my last customer entry override the previous entry instead of adding it to the customer object? JS
  Any help would be much appreciated.</p>
  <pre><code>class Bank {
      constructor() {
          this.customers = {};
  
  
      }
  }
  
  Bank.prototype.addCustomer = function (customer) {
      this.customers = customer;
      return this;
  
  }
  var bank = new Bank();
  var newCustomer1 = bank.addCustomer('Curtis');
  var newCustomer2 = bank.addCustomer('Alice');
  
  console.log(bank.customers);
  
  </code></pre>