javascript - How to correctly chain Angular HttpPomise -

i had angular service function:

    service.getitembyid = function(id) {         var hp = $http({method: "get", url: "service/open/item/id",             headers: {"token": $rootscope.user.token},             params: {"id": id}});          return hp;     }; 

i need manipulate returned values before sending them on , want keep httppromise structure intact since controller code written expect success , failure functions of httppromise present.

i have rewritten service this:

    service.getitembyid = function(id) {         var hp = $http({method: "get", url: "service/open/item/id",             headers: {"token": $rootscope.user.token},             params: {"id": id}});          var newhp = hp.success(                 function(data, status, headers, config) {                     data.x = "test";  //todo: add full manipulation                     alert("success");                     return hp;                 });          return newhp;     }; 

this code works , work regardless of whether return hp or newhp. question is: proper form of httppromise chaining?

calling .success returns same deferred object called on. not create new object. register success callback on deferred.

you can use new reference, or keep old reference:

service.getitembyid = function(id) {     var hp = $http({method: "get", url: "service/open/item/id",         headers: {"token": $rootscope.user.token},         params: {"id": id}});      hp.success(             function(data, status, headers, config) {                 data.x = "test";  //todo: add full manipulation                 alert("success");                 return hp;             });      return hp; }; 

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if want to, chain them all, , return deferred object directly:

service.getitembyid = function(id) {     return $http({         method: "get",         url: "service/open/item/id",         headers: {"token": $rootscope.user.token},         params: {"id": id}     })     .success(function(data, status, headers, config) {         data.x = "test";         alert("success");     }); };