OK I had to write things down to try and make sense of this. If anyone is like me, consider this loop that loops 5 times... maybe it will help? defines = 0

OK I had to write things down to try and make sense of this. If anyone is like me, consider this loop that loops 5 times... maybe it will help? defines = 0 tests = 0 increments = 0 defines++ for (let i = 0; i < 5; i++) { tests++ increments++ } console.log(`defines: ${defines}, tests: ${tests}, increments: ${increments}`) For the sake of space I'm not going too copy nested versions of that, but imagine nesting it two and then three levels deep. 1 level will increment 5 (5^1) times 2 levels will increment 25 (5^2) times 3 levels will increment 125 (5^3) times More interesting are the number of definitions and tests: levels tests defines 1 15 1 2 30 6 3 155 31 But I don't know is how the interpreter works and whether it has tricks to shrink those numbers; those just reflect my naive mental model of how things work.