CODEWITHSUNDEEP
angularjsangularng-upgrade
Chris
Chris

Reputation: 27384

ngUpgrade performance considerations

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.

Upvotes: 8

Views: 2082

Answers (3)

Oleg Dikusar
Oleg Dikusar

Reputation: 2503

You should know that there are two ways to bootstrap a Hybrid App:

  1. UpgradeModule - bootstraps both the AngularJS (v1) and Angular (v6) frameworks in the Angular zone

  2. DowngradeModule - bootstraps AngularJS outside of the Angular zone and keeps the two change detection systems separate.

I have tried both ways. And I recommend using DowngradeModule - it's better for performance and memory leaks.

Upvotes: 3

Nicolas Gehlert
Nicolas Gehlert

Reputation: 3253

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.

Upvotes: 5

jssayin
jssayin

Reputation: 93

I am currently in similar shoes and the only thing I know is that the digest cycles of A1 and A2 trigger each other. This makes me think that during upgrade, things will be slower... I will update you if I find anything different in coming months. https://angular.io/docs/ts/latest/guide/upgrade.html#!#change-detection

Everything that happens in the application runs inside the Angular 2 zone. This is true whether the event originated in Angular 1 or Angular 2 code. The zone triggers Angular 2 change detection after every event. The UpgradeModule will invoke the Angular 1 $rootScope.$apply() after every turn of the Angular zone. This also triggers Angular 1 change detection after every event.

Upvotes: 2

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