JavaScript “new Array(n)” and “Array.prototype.map” weirdness

Question

I\'ve observed this in Firefox-3.5.7/Firebug-1.5.3 and Firefox-3.6.16/Firebug-1.6.2

When I fire up Firebug:

Answer 1

ES6 solution:

[...Array(10)]

Doesn't work on typescript (2.3), though