AngularJS - get previous selected option after ng-click on a ng-repeat

Issue

I need to get the previous value that was selected on a given ng-repeat so that I can return it back in case of business demand. How can I achieve this?

I have a ng-click, but at the point of the event click I already have the new item selected, but I need the old one too if it exists.

PS: I'm new to angular js, hence pardon my noobie question!

Thanks.

Solution

You can keep an array of the selections 'history'

angular.module('myApp', [])
  .controller('myCtrl', ['$scope', function($scope) {
    let selHistory = []
    $scope.selectThing = "val2"
    $scope.recVal = function() {
      if (selHistory.length === 0 || selHistory[selHistory.length - 1] !== $scope.selectThing)
        selHistory.push($scope.selectThing)

      console.log("The history of selections: ", selHistory);
    }
    $scope.recVal(); // push our intiial variable in there

    $scope.revert = function() {
      if (selHistory.length > 0) {
        selHistory.pop();
        $scope.selectThing = selHistory[selHistory.length - 1]
        console.log("The history of selections: ", selHistory);
      }
    }
  }]);

<script src="https://cdnjs.cloudflare.com/ajax/libs/angular.js/1.7.5/angular.min.js"></script>
<div ng-app="myApp" ng-controller="myCtrl">
  <select ng-change="recVal()" ng-model="selectThing">
    <option value='val1'>1</option>
    <option value='val2'>2</option>
    <option value='val3'>3</option>
  </select>
  <button ng-click='revert()'>Revert</button>
</div>

Answered By - Kinglish