您的工厂无法访问您的 $scope，因为它不在同一范围内.

Your factory can't access your $scope, since it's not in the same scope.

试试这个:

recipeApp.controller('recipeController', function ($scope, groceryInterface) {

    $scope.addToList = groceryInterface.addToList;
    $scope.clearList = groceryInterface.clearList;
    $scope.add       = groceryInterface.add;
    $scope.addUp     = groceryInterface.addUp;
}

recipeApp.factory('groceryInterface', function () {

    var factory = {};

    factory.addToList = function (recipe) {
        this.groceryList.push(recipe);
    }

    factory.clearList = function() {
        var last = this.prevIngredients.pop();
    }
});

或者，您可以尝试使用更面向对象的方法:

Alternatively, you can try using a more object oriented approach:

recipeApp.controller('recipeController', function ($scope, groceryInterface) {

    $scope.groceryFunc = new groceryInterface($scope);
}

recipeApp.factory('groceryInterface', function () {

    function Factory ($scope) {

        this.$scope = $scope;
    }

    Factory.prototype.addToList = function (recipe) {
        this.$scope.groceryList.push(recipe);
    }

    Factory.prototype.clearList = function() {
        var last = this.$scope.prevIngredients.pop();
    }

    return Factory;
});