`ui-router` $stateParams vs. $state.params

The documentation reiterates your findings here: https://github.com/angular-ui/ui-router/wiki/URL-Routing#stateparams-service

If my memory serves, $stateParams was introduced later than the original $state.params, and seems to be a simple helper injector to avoid continuously writing $state.params.

I doubt there are any best practice guidelines, but context wins out for me. If you simply want access to the params received into the url, then use $stateParams. If you want to know something more complex about the state itself, use $state.

Another reason to use $state.params is for non-URL based state, which (to my mind) is woefully underdocumented and very powerful.

I just discovered this while googling about how to pass state without having to expose it in the URL and answered a question elsewhere on SO.

Basically, it allows this sort of syntax:

<a ui-sref="toState(thingy)" class="list-group-item" ng-repeat="thingy in thingies">{{ thingy.referer }}</a>

EDIT: This answer is correct for version 0.2.10. As @Alexander Vasilyev pointed out it doesn't work in version 0.2.14.

Another reason to use $state.params is when you need to extract query parameters like this:

$stateProvider.state('a', {  url: 'path/:id/:anotherParam/?yetAnotherParam',  controller: 'ACtrl',});module.controller('ACtrl', function($stateParams, $state) {  $state.params; // has id, anotherParam, and yetAnotherParam  $stateParams;  // has id and anotherParam}