I wish instead of this marketing article there were technical details, for example: what method of change tracking is used (proxies Vue-style or recomputing everything React-style).

Also I didn't understand the phrase about JS "overflowing stack" with 150 000 objects. I created a list of 150 000 objects with the following code:

    var list = [];
    for (var i = 0; i < 150000; i++) { list.push({ id: i, name: `Name ${i}`, weight: i * 100 });  }

According to profiler, this array (with objects) uses 14 Mb, where 2 Mb is array and the rest are objects and strings. Running list.find() without any indexes also doesn't overflow the stack. With indexes it would probably be lightning fast and won't need any WASM and complications.

JS is not that slow. And if you do numeric computations (i.e. multiplication of numbers in large arrays) the code gets compiled and runs pretty fast.