Function dataURLProcessor

deps/undici/src/lib/web/fetch/data-url.js:21–116

@param {URL} dataURL

(dataURL)

// https://fetch.spec.whatwg.org/#data-url-processor
/** @param {URL} dataURL */
function dataURLProcessor (dataURL) {
  // 1. Assert: dataURL’s scheme is "data".
  assert(dataURL.protocol === 'data:')

  // 2. Let input be the result of running the URL
  // serializer on dataURL with exclude fragment
  // set to true.
  let input = URLSerializer(dataURL, true)

  // 3. Remove the leading "data:" string from input.
  input = input.slice(5)

  // 4. Let position point at the start of input.
  const position = { position: 0 }

  // 5. Let mimeType be the result of collecting a
  // sequence of code points that are not equal
  // to U+002C (,), given position.
  let mimeType = collectASequenceOfCodePointsFast(
    ',',
    input,
    position
  )

  // 6. Strip leading and trailing ASCII whitespace
  // from mimeType.
  // Undici implementation note: we need to store the
  // length because if the mimetype has spaces removed,
  // the wrong amount will be sliced from the input in
  // step #9
  const mimeTypeLength = mimeType.length
  mimeType = removeASCIIWhitespace(mimeType, true, true)

  // 7. If position is past the end of input, then
  // return failure
  if (position.position >= input.length) {
    return 'failure'
  }

  // 8. Advance position by 1.
  position.position++

  // 9. Let encodedBody be the remainder of input.
  const encodedBody = input.slice(mimeTypeLength + 1)

  // 10. Let body be the percent-decoding of encodedBody.
  let body = stringPercentDecode(encodedBody)

  // 11. If mimeType ends with U+003B (;), followed by
  // zero or more U+0020 SPACE, followed by an ASCII
  // case-insensitive match for "base64", then:
  if (/;(?:\u0020*)base64$/ui.test(mimeType)) {
    // 1. Let stringBody be the isomorphic decode of body.
    const stringBody = isomorphicDecode(body)

    // 2. Set body to the forgiving-base64 decode of
    // stringBody.
    body = forgivingBase64(stringBody)