PDF.js version: 3.5.141

These two properties should be marked as not mandatory as they are initialized if not present
const viewerVersion =
      typeof PDFJSDev !== "undefined" ? PDFJSDev.eval("BUNDLE_VERSION") : null;
    if (version !== viewerVersion) {
      throw new Error(
        `The API version "${version}" does not match the Viewer version "${viewerVersion}".`
      );
    }
    this.container = options.container;
    this.viewer = options.viewer || options.container.firstElementChild;
    if (typeof PDFJSDev === "undefined" || PDFJSDev.test("GENERIC")) {
      if (this.container?.tagName !== "DIV" || this.viewer?.tagName !== "DIV") {
        throw new Error("Invalid `container` and/or `viewer` option.");
      }
      if (
        this.container.offsetParent &&
        getComputedStyle(this.container).position !== "absolute"
      ) {
        throw new Error("The `container` must be absolutely positioned.");
      }
    }