vendor/html-css-sanitizer-bundle.js
function encodeIfExists2(unescapedPart, extra) {
  if ('string' == typeof unescapedPart) {
    return encodeURI(unescapedPart).replace(extra, encodeOne);
  }
  return null;
}
function encodeIfExists2(unescapedPart, extra) {
  if ('string' == typeof unescapedPart) {
    return encodeURI(unescapedPart).replace(extra, encodeOne);
  }
  return null;
}
function encodeIfExists2 ( unescapedPart , extra ) { if ( 'string' == typeof unescapedPart ) { return encodeURI ( unescapedPart ) . replace ( extra , encodeOne ) ; } return null ; }
if unescapedPart is non null, then escapes any characters in it that aren't
valid characters in a url and also escapes any special characters that
appear in extra.

@param unescapedPart {string}
@param extra {RegExp} a character set of characters in [\01-\177].
@return {string|null} null iff unescapedPart == null.
if unescapedPart is non null then escapes any characters in it that aren t valid characters in a url and also escapes any special characters that appear in extra .