convert a number from base 2 to base 8 in javascript

To convert a number from base 2 to base 8, we can follow these steps:

1. Split the binary number into groups of three digits each, starting from the rightmost digit. If the leftmost group has less than three digits, add leading zeros to make it three digits.
2. Convert each three-digit group to its octal equivalent using the following chart:

| Binary | Octal | |--------|-------| | 000 | 0 | | 001 | 1 | | 010 | 2 | | 011 | 3 | | 100 | 4 | | 101 | 5 | | 110 | 6 | | 111 | 7 |

3. Concatenate the octal equivalents of each group to get the final result.

Here's the JavaScript code to implement this algorithm:

index.tsx
function binaryToOctal(binaryNum) {
  // Step 1: Split into groups of three digits
  let binaryGroups = binaryNum.match(/.{1,3}/g);
  if (binaryGroups[0].length < 3) {
    binaryGroups[0] = binaryGroups[0].padStart(3, '0');
  }
  
  // Step 2: Convert each group to octal
  let octalGroups = binaryGroups.map(group => {
    return parseInt(group, 2).toString(8);
  });
  
  // Step 3: Concatenate the octal groups
  return octalGroups.join('');
}
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Here's an example usage:

index.tsx
let binaryNum = '10110111';
let octalNum = binaryToOctal(binaryNum);
console.log(octalNum); // Output: 267
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