Reverse Number Patterns in Javascript

Here are some of the number Patterns in javascript that are mostly asked in Interview Questions.

function printPattern() {
  // First half of the pattern
  for (let i = 1; i <= 4; i++) {
    let finalOutput = '';
    for (let j = 1; j <= i; j++) {
      finalOutput += j;
    }
    console.log(finalOutput);
  }

  // Second half of the pattern
  for (let i = 4; i >= 1; i--) {
    let finalOutput = '';
    for (let j = 1; j <= i; j++) {
      finalOutput += j;
    }
    console.log(finalOutput);
  }
}

printPattern();


output
1
12
123
1234
1234
123
12
1

function printPattern() {
  // First half of the pattern
  for (let i = 1; i <= 4; i++) {
    let finalOutput = '';
    for(let k=1;k<=4-i;k++){
        finalOutput += " "
    }
    for (let j = 1; j <= i; j++) {
      finalOutput += j + " ";
    }
    console.log(finalOutput);
  }

  // Second half of the pattern
  for (let i = 4; i >= 1; i--) {
    let finalOutput = '';
      for(let k=1;k<=4-i;k++){
        finalOutput += " "
    }
    for (let j = 1; j <= i; j++) {
      finalOutput += j + " ";
    }
    console.log(finalOutput);
  }
}

printPattern();

output
   1 
  1 2 
 1 2 3 
1 2 3 4 
1 2 3 4 
 1 2 3 
  1 2 
   1