InfinitList javascript

infinitListJavscript.js

//repeat :: a -> [a]
var repeat = function(a){
    return [a].concat( repeat(a) );
}

// take :: Int -> [a] -> [a]
var take = function(n, a){
    if(a.length == 0 || n <= 0 ) return [];
    return a[0].concat( take( n - 1, a.slice(1) ) );
}

var r = take(5, repeat(5));
console.log(r);
// You can’t make an infinite list that way because JavaScript is an eager language. It will just keep building the list forever
// However you can use generators
var repeat = function *(a) {
  while (true) yield a
}

var take = function *(n, a) {
  for (var x of a) {
    if (n == 0) break

    yield x
    n--
  }
}

var r = take(5, repeat(5))
console.log([... r])