How to display pyramid using JavaScript?

Question

Here is the code to display pyramid but its not exactly producing required output.

Answer 1

If we're talking about the 'pyramid' problem, then this would be an appropriate solution.

function pyramid(n) { // If (e.g.) n=3;
  const columnLength = (n * 2) - 1; // 5 
  let middle = Math.floor(columnLength / 2) // middle would be 2
  for(let row=0; row row=2;col=3; row=3;col=5; row=5;col=9
// We got 2 sides, right? 
// So, before we insert '#' we need to make sure the following logic is met:
// Look at:  (middle - row) as being the left side and  (middle + row) as the right one.
// Only if both conditions are met, we want to insert the "#" sign
      if(middle - row <= col && middle + row >= col ) {
         res += '#';
      } else {
// If '#' is NOT inserted then we want to insert something else, right?! 
// In our case that would be an empty string
        res += ' ';
      }
    }
    console.log(res);
  }
}

pyramid(3);

---

And if we want to be extra 'fancy, we coučld implement recursion:

function recursiveP(n, row=0, res='') { // IMPORTANT: Pass some default values
      const columnLength = (n * 2) - 1;
      let middle = Math.floor(columnLength / 2);
      // This is our EXIT condition, meaning, if have the n number of rows, our work is done!!
      if(n === row) {
        return;
      }
      //  *** Moving on ***
      //   Initially, this will be skipped, and we'll go to the next check and add the appropriate character,
      //   however, after we're finished w/ creating the 1st row we'll hit this check, we'll print the previously generated result,
      //   and call the function again, but this time incrementing the ROW value. This will continue until the 1st check is met
      if(res.length === columnLength) {
         console.log(res);
         return recursiveP(n, row + 1);
      }
      //   Here we're creating the columns and in each, we're inserting the appropriate char
      if(middle - row <= res.length && middle + row >= res.length ) {
         res += '#';
      } else {
         res += ' ';
      }
      //Initial [recursive] function call
      recursiveP(n, row, res);
    }
    
    recursiveP(6);