拿下奇怪的前端报错（六）：多摄手机webrtc拉取视频流会导致应用崩溃，从而无法进行人像扫描

const fallbackMap = new Map<string, number[]>();
// 加入需要执行回退方案的map
fallbackMap.set("ELS-AN00", [0, 4]);
let preferFallback = false;
let preferIndexs = [0, 4];
{
  const ua = navigator.userAgent;
  for (const key of fallbackMap.keys()) {
    if (ua.includes(key)) {
      preferFallback = true;
      preferIndexs = fallbackMap.get(key)!;
      console.info(`hite ${key}`);
      break;
    }
  }
}
// 如果ua匹配上，查看是否有需要标记失败的
if (shouldCameraFallback()) {
  markDeviceIdTested();
}

export const markDeviceIdTested = async (curId?: string) => {
  const vlist = await getVideoDevices();
  if (!vlist) {
    return;
  }
  const checkingDevice = localStorage.getItem("capture_checking_device");
  const sucList = getSavedList(
    "capture_success_list",
    preferIndexs
  ) as number[];
  const cidx = vlist.findIndex((v) => v.deviceId === curId);
  if (
    (checkingDevice && checkingDevice === curId) ||
    (!checkingDevice && curId)
  ) {
    if (!sucList.includes(cidx)) {
      sucList.push(cidx);
      localStorage.setItem("capture_success_list", JSON.stringify(sucList));
    }
    localStorage.removeItem("capture_checking_device");
    return;
  }
  if (!checkingDevice) {
    return;
  }
  const failList = getSavedList("capture_fail_list", []) as number[];
  failList.push(cidx);
  localStorage.setItem("capture_fail_list", JSON.stringify(failList));
};

// 检查是否需要兼容模式 - 不然可用facingMode控制相机切换
export const shouldCameraFallback = () => {
  return !!localStorage.getItem("camera_fallback_used") || preferFallback;
}
// 根据限制获取设备id
export const getDeviceId = (v?: ConstrainDOMString): string | undefined => {
  return Array.isArray(v)
    ? v[0]
    : typeof v === "object"
    ? getDeviceId(v.exact)
    : v;
}
// 拉流前标记正在检测的设备id
export const markDeviceIdTest = (deviceId: string) => {
  localStorage.setItem("capture_checking_device", deviceId);
}
// 从localstorage读取列表数据
function getSavedList (key: string, def: any) {
  const str = localStorage.getItem(key);
  try {
    const e = JSON.parse(str || "");
    return e || def;
  } catch (error) {
    return def;
  }
}
// 获取摄像头列表
async function getVideoDevices ()  {
  // **************下面的内容需要自己调整，设备枚举前要先获取权限不然获取不到设备列表
  await permission.checkVideoPermission();
  const list = await navigator.mediaDevices.enumerateDevices();
  return list.filter((e) => e.kind === "videoinput").sort();
}

export const getNextDeviceId = async (curId: string) => {
  // ***** 需要自己调整下面的相机权限获取方法
  await permission.checkVideoPermission();
  const list = await navigator.mediaDevices.enumerateDevices();
  const vlist = list.filter((e) => e.kind === "videoinput");
  let sucList = getSavedList("capture_success_list", preferIndexs) as number[];
  let cidx = vlist.findIndex((v) => v.deviceId === curId);
  if (cidx === -1) {
    cidx = 0;
    localStorage.setItem("capture_success_list", JSON.stringify(preferIndexs));
    sucList = preferIndexs;
  }
  if (sucList.includes(cidx)) {
    // 如果成功列表有两个摄像头了，就用这俩，就不会发生崩溃啦！！
    if (sucList.length > 1) {
      const lidx = sucList.indexOf(cidx);
      const nSucIdx = lidx === sucList.length - 1 ? 0 : lidx + 1;
      const nIdx = sucList[nSucIdx];
      const dev = vlist[nIdx];
      console.log(`use sucList ${nSucIdx} - realIndex ${nIdx} `);
      return dev.deviceId;
    }
  }
  const failList = getSavedList("capture_fail_list", []) as number[];
  // 检查下一个可用idx
  const ne = vlist.find(
    (e, idx) => !failList.includes(idx) && e.deviceId !== curId
  );
  return ne?.deviceId;
};

const updateSwitchParams = async () => {
  if (!shouldCameraFallback()) {
    facingMode = facingMode === "user" ? "environment" : "user";
    return;
  }
  await markDeviceIdTested(deviceId);
  deviceId = (await getNextDeviceId(deviceId)) || "";
  if (!deviceId) {
    d.canSwitch = false;
  }
};

const getMediaConfig = () => {
  const video = {
    width: { min: 640, ideal: 1280 },
    height: { min: 480, ideal: 720 },
  } as any;
  const audio = mode === 2;
  if (shouldCameraFallback()) {
    if (deviceId) {
      video.deviceId = deviceId;
    }
    markDeviceIdTest(deviceId);
    return {
      video,
      audio,
    };
  }
  if (facingMode) {
    video.facingMode = facingMode;
  }
  if (deviceId && deviceIdFaceMode === facingMode) {
    video.deviceId = deviceId;
  }
  return {
    video,
    audio,
  };
}

const config = getMediaConfig();
  console.log("camera", config);
return navigator.mediaDevices
    .getUserMedia(config)