docs: function toLength (str, length, format) {
    if (!str) {
      return emptyString(length)
    }
    let newStr = str.toString()
    let diff = cleanString(str).length - length
    if (diff < 0) {
      diff *= -1
    }
    if (!format || format === 'l') {
      newStr = newStr + emptyString(diff)
    } else if (format === 'r') {
      newStr = emptyString(diff) + newStr
    } else { // (format === "c")
      const s = diff / 2
      newStr = emptyString(Math.ceil(s)) + newStr + emptyString(Math.floor(s))
    }
    return newStr
  }