Can angularjs routes have default parameter values

问题:

Can I set a default value of a parameter of a route in AngularJS? Is there a way to have /products/123 and /products/ handled by the same route ?

I'm looking to refactor my existing code, which looks like:

myModule.config(['$routeProvider', function($routeProvider) {
    $routeProvider.
     when('/products/', {templateUrl: 'products.html', controller: ProductsCtrl}).            
     when('/products/:productId', {templateUrl: 'products.html', controller: ProductsCtrl})
}]);


function ProductsCtrl($scope, $routeParams) {
    $scope.productId = typeof($routeParams.productId) == "undefined" ? 123 : $routeParams.productId;
}

It works, but it's not very elegant. Is there a better way ?

回答1:

AngularJS does not allow default values for route parameters.

But routes (in AngularJS) should not have default parameters.

Resources could have default parameters.

In AngularJS if you want a route with an optional parameter, these are actually two different routes.

Why?

• Routes should be simple

• Routes does not allow regular expressions matching for parameters

• Routes are not something which exposes an API to work in your application (unlike Resources do). Routes are just configuration which connects a URL with a template and a controller. Thus having more routes is better:

  • It is clear which route maps to which url.

  • It is more verbose, but simpler to read. Having more complex routes would create a steeper learning curve where AngularJS does not need one.

Unlike server-side frameworks which have routes

• AngularJS routes do not have names.
• You do not build URLs from the defined routes.
• You do not have logic (a.k.a functions) in the routes definitions.

Simpler routes = more lines to define them = less headaches working with them.

NOTE: Please keep in mind the question and this answer are for an old version of AngularJS (1.0 I think) pre-dating the new routes/resources implementation.

回答2:

I recognize that this question is old, but still: Why don't you just redirect the "empty" URL to one containing the default productId?

myModule.config(['$routeProvider', function($routeProvider) {
    $routeProvider.
     when('/products/', {redirectTo: '/products/123'}).
     when('/products/:productId', {templateUrl: 'products.html', controller: ProductsCtrl})
}]);

回答3:

I had a similar requirement. What i did was to create a function to resolve. Something like below

myModule.config(['$routeProvider', function($routeProvider) {
$routeProvider.
 when('/products/', resolveProduct()).            
 when('/products/:productId', resolveProduct())
}]);


function ProductsCtrl($scope, $routeParams) {
$scope.productId = $routeParams.productId;
}

function resolveProduct() {
   var routeConfig = {
      templateUrl: 'products.html', 
      controller: ProductsCtrl,
      resolve: {
         productId: ['$route', function($route){
            var params = $route.current.params;
            params.productId =  params.productId || 123;
         }]
      }
   }

   return routeConfig;
}

回答4:

With url: "/view/:id/:status?", You can indicate an optional parameter.

Just thought someone may need it.

回答5:

Not sure if this question is specific to $routeProvider but in $stateProvider, you can achieve this by

myApp.config(function($stateProvider) {

    $stateProvider
        .state('products', {
            url: '/:productId',
            templateUrl: "/dashboard/products.html",
            controller: 'ProductController',
            params: {
                productId: {
                  value: "defaultValue",
                  squash: true // or enable this instead to squash `productId` when empty
                } 
            }
        });
});