unicode() - Converts any string into a string of 6-character JS-compliant unicode code points.

unicode.js

/**
 * Converts any string into a string of 6-character JS-compliant unicode code
 * points.
 * @param {string} input
 *   The input that will be converted to a string of 6-character groups
 *   representing unicode code points.
 * @param {boolean} [asJSON=false]
 *   Optional, defaults to `false`.  Indicates if the returned string will be
 *   the JSON version of `input`.
 * @returns {string}
 *   A string where each character from `input` will be represented by one or
 *   more 6-character groups.  Each 6-character group will be a string that
 *   representing a unicode code point (between "\u0000" and "\uFFFF").  If
 *   `asJSON` is `true` this string will begin and end with a double-quote.
 */
function unicode(input, asJSON=false) {
  for (var r = '', i = input.length; i--;) {
    r = '\\u' + ('000' + input.charCodeAt(i).toString(16)).slice(-4) + r;
  }
  return asJSON ? '"' + r + '"' : r;
}

~io-config.jsonc

{
  // Name of the function responsable for transforming the input into the output.
  "transform": "unicode",
  // Type of YourJS IO-App
  "type": "instant",
  // Where to find the code that will be eval'd.
  "files": ["unicode.js"]
}

IO App:
https://www.yourjs.com/gist-io/938926a9a7f6f9e1d5d24e6f36f8ec71