Angular 2 - Checking for server errors from subscribe

Question

I feel like this scenario should be in the Angular 2 docs  but I can t find it anywhere    Here s the scenario   submit a form  create object  that is invalid on the server server returns a 400 bad request with errors I display on the form after the subscribe comes back  I want to check an error variable or something  ie  if no errors   then route to newly created detail page    I imagine it working something like this   this projectService create project       subscribe          result   gt  console log result           error   gt                this errors   error                      if   this errors          route to new page     I m very new to Angular 2 so this may come from my lack of understanding in how an Observable works  I have no issue with displaying that data on the form  but can t figure out how to see it within the ts component  I really just want to check the success fail of the http create

User · Answer

You can achieve with following way      this projectService create project       subscribe          result   gt             console log result                      error   gt                console log error               this errors   error                      if   this errors          route to new page

User · Answer

As stated in the relevant RxJS documentation  the  subscribe   method can take a third argument that is called on completion if there are no errors  For reference     onNext   Function   Function to invoke for each element in the observable sequence   onError   Function   Function to invoke upon exceptional termination of the observable sequence   onCompleted   Function   Function to invoke upon graceful termination of the observable sequence    Therefore you can handle your routing logic in the onCompleted callback since it will be called upon graceful termination  which implies that there won t be any errors when it is called   this httpService makeRequest        subscribe        result   gt               Handle result         console log result                 error   gt            this errors   error                      gt                onCompleted  callback             No errors  route to new page here                  As a side note  there is also a  finally   method which is called on completion regardless of the success failure of the call  This may be helpful in scenarios where you always want to execute certain logic after an HTTP request regardless of the result  i e   for logging purposes or for some UI interaction such as showing a modal    Rx Observable prototype finally action  Invokes a specified action after the source observable sequence terminates gracefully or exceptionally   For instance  here is a basic example  import   Observable   from  rxjs Rx   import  rxjs add operator finally            this httpService getRequest        finally      gt             Execute after graceful or exceptionally termination       console log  Handle logging logic                   subscribe         result   gt               Handle result         console log result                 error   gt            this errors   error                      gt               No errors  route to new page

[http] Angular 2 - Checking for server errors from subscribe

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[http] Angular 2 - Checking for server errors from subscribe

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