Read diagram data from a ZIP file

sequenceDiagram.js

const params = new URL(document.location).searchParams;
const diagramUrl = params.get('diagram');
let diagramData;
if (diagramUrl.endsWith('.zip')) {
  const resourceId = params.get('resourceId');
  if (!resourceId) throw new Error(`resourceId is required with diagram resource ZIP file`);

  const localStorageKey = ['appmap', 'diagram', diagramUrl].join('-');
  let diagramDataEncoded;
  if (!['false', 'no'].includes(params.get('cache')))
    diagramDataEncoded = localStorage.getItem(localStorageKey);
  if (diagramDataEncoded) {
    diagramData = await base64UrltoBlob(diagramDataEncoded);
  } else {
    diagramData = await (await fetch(diagramUrl)).blob();
    diagramDataEncoded = await blobToBase64(diagramData);
    localStorage.setItem(localStorageKey, diagramDataEncoded);
  }

  // Creates a BlobReader object used to read `zipFileBlob`.
  const zipFileReader = new BlobReader(diagramData);
  // Creates a TransformStream object, the content of the first entry in the zip
  // will be written in the `writable` property.
  const dataStream = new TransformStream();
  // Creates a Promise object resolved to the content of the first entry returned
  // as text from `helloWorldStream.readable`.
  const dataStreamPromise = new Response(dataStream.readable).text();

  // Creates a ZipReader object reading the zip content via `zipFileReader`,
  // retrieves metadata (name, dates, etc.) of the first entry, retrieves its
  // content into `helloWorldStream.writable`, and closes the reader.
  const zipReader = new ZipReader(zipFileReader);
  const entries = await zipReader.getEntries();
  const requestedEntry = entries.find((entry) => entry.filename === resourceId);
  if (!requestedEntry) throw new Error(`Resource ${resourceId} not found in ${diagramUrl}`);

  await requestedEntry.getData(dataStream.writable);
  await zipReader.close();
  const diagramDataRaw = await dataStreamPromise;
  diagramData = JSON.parse(diagramDataRaw);
} else {
  diagramData = (await fetch(diagramUrl)).json();
}

const { ui } = this.$refs;

ui.loadData((await diagramData) || {});