angular - Is there any difference in overhead when using Observables as opposed to promises? -

-

i considering whether use observables or promises in new angular 2 app. told observables can promises can , more, curious how overhead observables require compared promises. has run benchmark tests? there reasons left use promises?

whereas both observables , promises deal asynchronous processing, there differences:

  • observables can canceled. promises can't.
  • observables lazy , executed when callbacks subscribed them. promises executed when created.
  • observables can handle several events whereas promises can resolved once.
  • observables provide set of operators create asynchronous data flow (like map, flatmap, filter, ...)

Comments

Post a Comment

Popular posts from this blog

magento2 - Magento 2 admin grid add filter to collection -

-
i created grid in admin xml ui components. need filter collection via url parameter , dont know how achieve that. tried inject requestinterface collection, filter didnt work. di.xml <virtualtype name="slidelistingdataprovider" type="magento\framework\view\element\uicomponent\dataprovider\dataprovider"> <arguments> <argument name="collection" xsi:type="object" shared="false">xxx\xxx\model\resourcemodel\grid\slide\collection</argument> <argument name="filterpool" xsi:type="object" shared="false">slidelistingfilterpool</argument> <!-- define new object filters --> </arguments> </virtualtype> <virtualtype name="slidelistingfilterpool" type="magento\framework\view\element\uicomponent\dataprovider\filterpool"> <arguments> <argument name="applier
Read more

Android volley - avoid multiple requests of the same kind to the server? -

-
i using volley upload list of images server. happens within service. once image uploaded remove list. problem arises when internet connection breaks. when internet connection breaks , comes again thinking of adding images yet uploaded request queue. this can result in more 1 copy of same image saved on server request same image might have gone through before getting rseponse. how can address scenario? i'm not quite sure why you're using service schedule requests volley automatically runs it's request in seperate thread. nevertheless can listen both request results, successful , unsuccessful adding listeners. you can remove image list schedule request using volley. if succeeds can carry on desired, if fails can add again list. public static request getimageuploadrequest(final string image) { response.listener<t> responselistener = new response.listener<t>() { @override public void onresponse(t response
Read more

Combining PHP Registration and Login into one class with multiple functions in one PHP file -

-
i'm trying combine registration, activation , login scripts php website backend script front end developer can pass variables different forms to. my question whether appropriate approach this. don't want have lot of php files different pieces of application developing. far have written following 2 functions login, register , activate user front end developer can call: <?php /** * created phpstorm. * user: karl * date: 26/07/2016 * time: 02:25 */ class users { function register_user($email, $password, $user_name) { $server_name = "localhost"; $u_name = "root"; $db_password = "root"; $db_name = "betamath_graspe"; //email notification variable $from_address="info@slack.com"; //registration form $msg_reg_user='username taken. please choose different username'; $msg_reg_email='email registered'; $msg_reg_active=&#
Read more