JSFiddle - React, Tailwind, and code Playground

JavaScript

function invertLines(M){
  var r=[];
  for(var i=M.length-1;i>=0;--i){
    r.push(M[i]);
  }
  return r;
}
var result = invertLines([
  [1,2,3],
  [4,5,6],
  [7,8,9]
]);
alert(result.join('\n'));