However, Javascript as the intermediate language does not follow. It may be true that a source-level intermediate representation has benefits, but the idea that

However, Javascript as the intermediate language does not follow. It may be true that a source-level intermediate representation has benefits, but the idea that the best intermediate representation is JS doesn't follow. For example, late-binding, boxing/heap-numbers, etc all serve to make it extremely difficult to maximize startup performance, or heap overhead. It also makes the VMs much more complex to deal with optimizing such languages. TypedArrays don't really fix the problem, they just introduce others. For example, by forcing your to implement your own manual memory management everywhere. This is somewhat problematic if you're compiling a language with GC into TypedArray heavy code, since there's no finalizers in JS or Reference queues, you can't really do automatic release if a regular heap object holds into pseudo-objects in manually allocated memory. The problem is particularly acute on mobile devices which are very resource constrained.