fix: Blocks memory leak (#100)

[darind]

Related to #100

[brysem]

Hi @darind,

Thank you for your effort! I've tested this PR in one of the larger apps I've made. The issue from #100 still seems to be present.

I tested it by using the app as normal and monitoring memory usage.

I've also tested it with a button that executes the following piece of code. This piece of code dramatically increases memory usage in V8. In JSC it does not.

var dispatch = function() {
    setTimeout(function() {
    for(var i=0; i < 100000; i++) {
        var p = new Promise((resolve, reject) => { resolve('') })
    }
    dispatch()
    }, 50)
}
dispatch();

[darind]

@brysem, by creating 100k promises every 50ms you are putting too much pressure on the JS engine. Here's the profiler graph when I reduce it to 5 seconds:

Make sure you leave some CPU cycles for the GC to complete.

As an alternative, we can make the PromiseProxy script conditional. It might break some plugins that rely on it but it will drastically improve performance.

[darind]

@NathanaelA, no I haven’t tried this on a real device in a fresh NS app. Does this crash occur in the Simulator?

But looking at the error, this looks like some issue with passing C strings as arguments to functions: https://github.com/NativeScript/ns-v8ios-runtime/blob/master/NativeScript/runtime/Interop.mm#L150

Are you sure that the crash doesn’t occur with a build from the master branch? Also is the use of the NSGetSizeAndAlignment function something new to the NS 8 core modules? Has this function been used before?

[NathanWalker]

This pr is rolled up in #111 and in rc for further validations, thank you @darind for all the efforts here ❤️