javascript - Improve Angular 1.2 Tree Control performance -


i have app based on angular 1.2 not made me, huge 1 many developers work on it. , have bugs fix it. 1 it's improve angular tree control performance. big problem documentation poor directive. if work , have ideas, please let me know.

my understanding want learn how improve performance of angular 1.2 app. if correct, there several things might affect angular 1.x app performance:

  1. non-angular related issues - things memory management, critical rendering path etc. beyond scope of answer.
  2. angular related issues - comes down 2 factors: $digest cycles , $watchers.

in event, need measure before start optimizing. chrome dev tools great way that.

what should do?

  1. track load - use performance tab (a.k.a. timeline tab) in order record problematic scenarios. here's guide that: https://developers.google.com/web/tools/chrome-devtools/evaluate-performance/reference
  2. track how many times $digest runs , find source using easy script in browser. here's example of one. script finds slowest digests, can track them down , handle them. issue might actions trigger many digests. can track doing like:

$rootscope.$watch(function(){console.log('digest!')});

this print out digest! on every cycle. can add debug point there or use chrome's monitor capability , async stack trace find out initiated $digest cycle. play make more informative. instance:

var lastdigest = 0;     var epsilon = 100; //ms - count close digests     var count = 1;     $rootscope.$watch(function(){         var currtime = new date().gettime();         if (currtime - lastdigest < epsilon) {             count++;             lastdigest = currtime;         } else {             console.log('digest! (' + count + ' found)');             count = 1;         }     });

in case above, you'll bunch digests came @ 100 ms period one, giving idea of how many digests action did. instance, if 1 click created 10 digests - it's cause alarm.

  1. track $watchers - that's kind of easy in own app: bindings, explicit $watch/$watchcollection statements etc. here's nice article it. use 1 time binding (you'd have upgrade 1.3 - see here) or use 3rd party (1.2 compatible bind once).

that's basics. of course, suggest measuring app first, decide do. answer gave direction.


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