leftpad (v4)

Revision 4 of this benchmark created by defcc on

Setup

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 leftpad2(str, len, ch) {
    if (!ch && ch !== 0) ch = ' ';
    return ('' + ch).repeat(Math.max(0, len - str.length)) + str
  }
  
  function leftpad3(str, len, ch) {
    str = ''+str;
  
    if (!ch && ch !== 0) ch = ' ';
    return new Array(Math.max(0, len - str.length + 1)).join(ch) + str;
  }

Test runner

Ready to run.

Testing in
TestOps/sec
while loop
leftpad('x', 40, 'hello world')
ready
repeat and slice
leftpad2('x', 40, 'hello world')
ready
array join
leftpad3('x', 40, 'hello world')
ready

Revisions

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