Staircase using repeat()

Runtime Complexity: O(n^2)

/*Create a staircase based on user input n.

steps(5) should return the below output:
"#    "
"##   "
"###  "
"#### "
"#####" 
*/

const steps = (n) => {
if( n > 0){
  for (let row = 0; row < n; row++) {
      let step = '';

      for (let col = 0; col < n; col++) {
        col <= row ? step += '#' : step += ' ';
      }
       console.log(step);
   }
   return
}
console.log(`please give a number greater than 0`)
}

steps(5);
/* Output
"#    "
"##   "
"###  "
"#### "
"#####" */

Demo

String.prototype.repeat()

Introduced in ES2015+, the repeat() method constructs and returns a new string which contains the specified number of copies of the string on which it was called, concatenated together.

Syntax: str.repeat(count)
count is an integer between 0 and infinity(positive) indicating the number of times to repeat the string.

Note: If the total length of the string to be returned equals or exceeds (1 << 28, i.e., 2^28) then, this method throws a RangeError as most modern browsers can’t handle strings longer than that.

if((str.length * count) >= 1 << 28) // This 

/* A simplified solution using String.prototype.repeat
 */
 
 const steps = (n) => {
  for(let i = 1; i <= n; i++) {
    let step = '#'.repeat(i) + ' '.repeat(n-i);
    console.log(step);
  }
}

steps(5);
/* Output
"#    "
"##   "
"###  "
"#### "
"#####" */

Demo