$ scope。$ watch（var，function）未定义不是函数

Question

I have this error: "undefined is not a function" comming up when trying to add a watch to the scope.

I can't find the error. Maybe i am just blind staring at this error for to long now. Why do i get a undefined function error when the $watch method is clearly defined on the scope ?

chColorPicker.controller('chColorPickerCtrl', function ($scope,$document,$element) {


    $scope.init = function (event)
    {

    }

    var colorObject = {
        r:'0', 
        g:'0', 
        b:'0', 
        hex:'#000000'
    };
    $scope = colorObject;
    $scope.Z1;
    $scope.Z2;

    var onChangeColor = function(newValue,oldValue)
    {
        console.log('change');
    }

    $scope.$watch("r",onChangeColor); //<-- the error appears here.
});

Answer 1

You're changing $scope:

$scope = colorObject;//error in this line

So, you get error when you use $scope.$watch() as it's not calling angular's $scope anymore.