DEC2BIN Function

DEC2BIN.js

// Copyright (c) 2012 Sutoiku, Inc. (MIT License)

function DEC2BIN(number, places) {
  // Return error if number is not a number
  if (isNaN(number)) return '#VALUE!';
  
  // Return error if number is not decimal, is lower than -512, or is greater than 511
  if (!/^-?[0-9]{1,3}$/.test(number) || number < -512 || number > 511) return '#NUM!';
  
  // Ignore places and return a 10-character binary number if number is negative
  if (number < 0) {
    return '1' + _s.repeat('0', 9 - (512 + number).toString(2).length) + (512 + number).toString(2);
  }

  // Convert decimal number to binary
  var result = parseInt(number, 10).toString(2);

  // Return binary number using the minimum number of characters necessary if places is undefined
  if (typeof places === 'undefined') {
    return result;
  } else {
    // Return error if places is nonnumeric
    if (isNaN(places)) return '#VALUE!';
    
    // Return error if places is negative
    if (places < 0) return '#NUM!';
    
    // Truncate places in case it is not an integer
    places = Math.floor(places);

    // Pad return value with leading 0s (zeros) if necessary (using Underscore.string)
    return (places >= result.length) ? _s.repeat('0', places - result.length) + result : '#NUM!';
  }
}