CODE EXAMPLE FOR JAVASCRIPT

How to make a toggle button in Angularjs

$scope.toggleButton = { inAddState: true };
$scope.update = (id, button) => {
    if (button.inAddState) {
        // logic to add
    } else {
        // logic to remove
    }
    // make sure you switch the state of the button at some point
    button.inAddState = !button.inAddState;
}

<button ng-click="update(data.id, toggleButton)" 
        class="btn {{ toggleButton.inAddState ? 'btn-primary' : 'btn-warning' }}"
        ng-bind="toggleButton.inAddState ? 'Add' : 'Remove'">
</button>