Q:

AngularJS update var in DOM referenced through function through controller

How can I update the value of a variable that's sent to a function, from within that same function?
HTML:
Message is: {{ msg }}
<button ng-click="updateVar(msg)">Update</button>

AngularJS:
$scope.msg = 'Init';

$scope.updateVar = function(varToUpdate) {
    varToUpdate = 'Var was updated!';
};

I can't do $scope.msg = 'Var was updated!';, since in the function I'm writing, I have many variables to potentially update, and I don't want to write different cases for every single variable.
Thank you!

A:

updateVar(msg) passes the value of $scope.msg to the function. 
You want to pass the variable name (or rather, the $scope property name): updateVar('msg')
And your function can then use the variable name to modify its value:
$scope.updateVar = function(varToUpdate) {
    $scope[varToUpdate] = 'Var was updated!';
};

