fix(ArrayObservation): ensure patch applied only once

[bigopon]

Things may still go horribly wrong if one ended up having two versions of aurelia-binding in the final bundle, but at least array patching won't happen twice. Also trim some unnecessary fat out

Edit: this will work as long as there is no difference between v1 and v2 ModifyArrayObserver / ModifyCollectionObserver

@EisenbergEffect Should we also replace global karma start with npm script ?

resolves #699

[3cp]

Suggest to log an error in console if it detects already patched, explain possible cause (3rd party plugin), and provide a link to suggested solution. Because duplicated aurelia-binding will inevitably introduce weird bug even without duplicated patch on Array.prototype.

[bigopon]

@huochunpeng nice suggestion 👍

[EisenbergEffect]

I love this idea. One change: could you switch the lookups back to using property access instead of array access? That will probably cause a perf change and since this is a hot code path, I'd rather not change that.

[bigopon]

@EisenbergEffect done

[EisenbergEffect]

Thanks!

[rmja]

Just a reminder that this change should be merged back into v1 in a minor or patch release to work properly😁

[fkleuver]

Just a reminder that this change should be merged back into v1 in a minor or patch release to work properly😁
^^^^^^

@EisenbergEffect Did this go into v1 too?

@bigopon nice one! :)

[EisenbergEffect]

working on a 1.7.2 release with this same fix

[EisenbergEffect]

1.7.2 and 2.1.3 both published with this fix.