let arr = Array.from(Array(5).keys());
Array(N).fill().map((e,i)=>i+1);
http://www.jstips.co/en/javascript/create-range-0/.n-easily-using-one-line/
let arr = Array.from(Array(5).keys());
Array(N).fill().map((e,i)=>i+1);
http://www.jstips.co/en/javascript/create-range-0/.n-easily-using-one-line/