title: How to stop original list from updating when cloned list is updated
body: <p>I want to stop <code>self.lineDetails</code> from being updated when I update <code>self.modifiedLineDetails</code>.</p>
  
  <pre><code>self.modifiedLineDetails = [];
  angular.forEach(self.lineDetails, function (value1, index1) {
      var lineDetail = self.lineDetails[index1];
      self.modifiedLineDetails.push(lineDetail)
  });
  console.log(self.lineDetails)
  angular.forEach(self.modifiedLineDetails, function (value10, index10) {
      var modifiedLineDetail = self.modifiedLineDetails[index10];
      if (modifiedLineDetail.SelectedCustomers.length &gt; 0) {
          modifiedLineDetail.SelectedCustomers = 1;
      } else {
          modifiedLineDetail.SelectedCustomers = 0
      }
  });
  console.log(self.modifiedLineDetails)
  </code></pre>
  
  <p>Previously I just assigned it like this <code>self.modifiedLineDetails = self.lineDetails</code> then I updated <code>self.modifiedLineDetails</code> but it wasn't working so I tried pushing it per line but <code>self.lineDetails</code> keeps updating.</p>