[z3t4]

Async code is hard to reason about. Async closures is what I like most about JavaScript (JS) though. Because JS pass all variables by value they get frozen in time when passed to a function. This make async code easier to reason about, as all variables are immutable.

[davidkunz]

In JavaScript, primitive types are passed by value, objects are passed by reference. But you won't have data races since JavaScript code is executed in a single thread.