Run results for: leftpad

Run details:

User agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/53.0.2785.116 Safari/537.36

Browser: Chrome 53

Operating system: Windows 7

Device Platform: Other

Date tested: 8 years ago

Test name	Executions per second
leftpad	3290181.5 Ops/sec
fastleftpad	1377307.9 Ops/sec

Script Preparation code:

function leftpad (str, len, ch) {
  str = String(str);
  var i = -1;
  if (!ch && ch !== 0) ch = ' ';
  len = len - str.length;
  while (++i < len) {
    str = ch + str;
  }
  return str;
}

function fastleftPad(value, size, pad) {
  if (value.length < size) {
    size -= value.length;
    var res = '';
    for(;;) {
      if (size & 1) res += pad;
        size >>= 1;
        if (size) pad += pad;
          else break;
    }
    return res + value;
  }
  return value;
}

function myleftpad (str, len, ch) {
  len=len-str.length;
  str+=ch.repeat(len);
  return str;
}

Tests:

leftpad
leftpad('anim',20,'0')
fastleftpad
fastleftPad('anim',20,'0')
mine
myleftpad('anim',20,'0')

blah

leftpad

fastleftpad

mine