ngUpgrade performance considerations

Question

I am trying to figure out if we can move our Angular 1 application to Angular 2. We have a sufficient amount of code to warrant using ng-upgrade as opposed to starting from scratch.

Our current application is pushing the performance limits of what Angular 1 is capable of. Hopefully Angular 2 will bring us some performance benefits.

My question is how much of an impact on performance our migration path will have (i.e. running Angular 1 alongside Angular 2 as per ng-upgrade guidelines)? Will it have a noticeable impact or will it not be noticeable in practice? My main concern during this period is run time speed as opposed to memory usage or load time.

Answer 1

Not sure if this thread is still relevant, I'll try to add some further notes. Currently we are at Angular 6, and the upgrade behavior has gotten a lot better.

For anyone having performance issues or thinking there might be issues I recommend have a look at the downgradeModule (https://angular.io/api/upgrade/static/downgradeModule#differences-with-upgrademodule)

You basically can either Upgrade the Angular 1 part or downgrade the Angular 2 part. On a first view they might seem similar but the behave fundamental differently. For anyone concerned with performance I definitely recommend the latter approach. This way you will have the improved performance for your new Angular 2 code and the old code runs at nearly the same/if not the same speed.

Even for fairly large applications it is a breeze and you very rarely have any performance problems.