Just many hours of time micro-optimising quirky projects like [1]. I could write a test specifically to demonstrate it... and write a little article... but just

Just many hours of time micro-optimising quirky projects like [1]. I could write a test specifically to demonstrate it... and write a little article... but just commenting here that in my humdrum experience - you might want to look into it yourself. I have tested and never seen any benefit in eg. initializing an array as [0,0,0,0,0,0,0,0,0,0,0,0,0,0,...] compared to Array(n) for (i=0;i<n; i++) A[i]=0 ... Ymmv. Takes moments to check with a benchmarking package of choice. I recommend avoiding testing it with any functional kind of expressions though, because they can be much slower than the old imperative style and obscure the picture. ...also, from a reasoning approach - why would a competitively accelerated language engine create an array full of holes as soon as one is declared? Why would the engine not try to optimally structure the type as it is used? This is something Chromes engines and Firefoxes appear to have done, quite impressively since many years back. [1] https://github.com/strainer/fencache.js https://github.com/strainer/fencache.js