Function forgivingBase64

lib/internal/data_url.js:265–300

* @param {string} data * @returns {object|'failure'}

(data)

 * @returns {object|'failure'}
 */
function forgivingBase64(data) {
  // 1. Remove all ASCII whitespace from data.
  data = RegExpPrototypeSymbolReplace(ASCII_WHITESPACE_REPLACE_REGEX, data, '');

  let dataLength = data.length;
  // 2. If data's code point length divides by 4 leaving
  // no remainder, then:
  if (dataLength % 4 === 0) {
    // 1. If data ends with one or two U+003D (=) code points,
    // then remove them from data.
    if (data[dataLength - 1] === '=') {
      --dataLength;
      if (data[dataLength - 1] === '=') {
        --dataLength;
      }
    }
  }

  // 3. If data's code point length divides by 4 leaving
  // a remainder of 1, then return failure.
  if (dataLength % 4 === 1) {
    return 'failure';
  }

  // 4. If data contains a code point that is not one of
  //  U+002B (+)
  //  U+002F (/)
  //  ASCII alphanumeric
  // then return failure.
  if (RegExpPrototypeExec(/[^+/0-9A-Za-z]/, data.length === dataLength ? data : StringPrototypeSlice(data, 0, dataLength)) !== null) {
    return 'failure';
  }

  const buffer = Buffer.from(data, 'base64');
  return new Uint8Array(buffer.buffer, buffer.byteOffset, buffer.byteLength);
}

/**
 * @see https://infra.spec.whatwg.org/#ascii-whitespace