Untitled

<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width">
  <title>JS Bin</title>
</head>
<body>

<script id="jsbin-javascript">
let result = [];

for(let i = 1; i <= 5; i++){
  let stringHolder = '';
for(let j = 1; j <= i; j++ ){

    stringHolder = stringHolder + ' '+ j

      }
   result.push(stringHolder);
  }

console.log(result);
</script>


<script id="jsbin-source-javascript" type="text/javascript">
let result = [];

for(let i = 1; i <= 5; i++){
  let stringHolder = '';
for(let j = 1; j <= i; j++ ){

    stringHolder = stringHolder + ' '+ j

      }
   result.push(stringHolder);
  }

console.log(result);


</script></body>
</html>