code: function isPrintable(c) {
    return 0x00020 <= c && c <= 0x00007E || 0x000A1 <= c && c <= 0x00D7FF && c !== 0x2028 && c !== 0x2029 || 0x0E000 <= c && c <= 0x00FFFD && c !== 0xFEFF /* BOM */ || 0x10000 <= c && c <= 0x10FFFF;
  }
docs: Returns true if the character can be printed without escaping. From YAML 1.2: "any allowed characters known to be non-printable should also be escaped. [However,] This isn’t mandatory" Derived from nb-char - \t - #x85 - #xA0 - #x2028 - #x2029.