[js] Another unexpected result

Sticking with the same theme as last post's short-circuit trickery, another Javascript operation that has an unexpected result (for me, anyway) is the assignment operation.

alert (x = 'hi');

The resultant friendly greeting demonstrates that the assignment operation not only assigns a value but actually evaluates as that value. This offers additional opportunities at simplification:

add(last_row = row);
return this.property = object.calculate(arg);
// etc.