Question

Heyo，

我有以下功能

async function fnIsOnScreenOnce(img, desc,iCounter,client,repeatDelay=0) {
  await timeout(repeatDelay);
  let screenshot= await client.screenshot()

  let buf = new Buffer(screenshot.value, 'base64');
  let img1 = cv.imdecode(buf)
  let result = img1.matchTemplate(img, 5).minMaxLoc(); 
  result.screenshot=img1;
  if (result.maxVal <= 0.65) {
      // Fail
      const msg = "Can't see object yet";
      throw new Error(result);
  }
        // All good
        console.log("result:"+result)
        logger.info("Found image on screen: "+desc);
        return result;
}

调用函数

function fnIsOnScreen(img,client, repeats = 5, desc, wait = 2000,repeatDelay) {
    logger.info("Looking for image on screen:" +desc +" with " + repeats + " repeats ");
    let iCounter = 0;
    let init = ()=> timeout(wait).then((asd)=>{
      const attempt = () => fnIsOnScreenOnce(img, desc, iCounter,client,repeatDelay).then((data=>{
        let imagepath=fnMarkOnImage(data.screenshot,img,data,outputDir)
        let description={};
        description.action="Is image on screen ?";
        description.desc=desc;
        description.repeats=repeats;
        description.wait=wait;
        description.img=imagepath;
        description.message="is this correct element ? if is then it was found correctly";
        fnPushToOutputArray(description)
      return data;
      })).catch(err => {
              console.log(JSON.stringify(err));
              console.log(err);
              console.log(err.result);
              iCounter++;
              if (iCounter === repeats) {
                  // Failed, out of retries
                  logger.info("Object not found : " + desc);
                  return Promise.reject("Object not found : " + desc);
              }
              // Retry after waiting
              return attempt();
          });
          return attempt();      
    })
    return init();


}

结果对象包含一些日期。错误结果包含{}对象，其中没有值。我需要得到所有的价值观。那么如何通过抛出新错误来传递结果对象以在catch中检索它？

Answer 1

返回带有错误的额外数据的一种方法是扩展Error类并将它们添加到自己的

class MyError extends Error {

    constructor(message, errorExtraParams) {
        super(message);
        this._errorExtraParams = errorExtraParams;
    }

    get errorExtraParams() {

        return this._errorExtraParams;

    }

}

throw new MyError("Error!!!", {})
//or
let mError =  new MyError("Error!!!", {})
console.log(mError.errorExtraParams)

但是我建议你不要使用throw Error，因为我不想因为不重要的原因而抛出错误。我的意思是，在你的情况下，没有理由抛出错误，因为没有错误，没有理由创建错误只是为了告诉你代码＆＃34;嘿，我没有找到图像＆＃34;而只是返回false。

async function fnIsOnScreenOnce(img, desc, iCounter, client, repeatDelay = 0) {
    await timeout(repeatDelay);
    let screenshot = await client.screenshot()

    let buf = new Buffer(screenshot.value, 'base64');
    let img1 = cv.imdecode(buf)
    let result = img1.matchTemplate(img, 5).minMaxLoc();
    result.screenshot = img1;
    if (result.maxVal <= 0.65) {
        const msg = "Can't see object yet";
        return false;
    }
    // All good
    console.log("result:" + result)
    logger.info("Found image on screen: " + desc);
    return result;
}

function fnIsOnScreen(img, client, repeats = 5, desc, wait = 2000, repeatDelay) {
    logger.info("Looking for image on screen:" + desc + " with " + repeats + " repeats ");
    let iCounter = 0;
    let init = () => timeout(wait).then((asd) => {

        let found = false;
        do {
            let found = await fnIsOnScreenOnce(img, desc, iCounter, client, repeatDelay)
        } while (found !== false && iCounter++ < 10)

        let imagepath = fnMarkOnImage(found.screenshot, img, found, outputDir)

        let description = {};
        description.action = "Is image on screen ?";
        description.desc = desc;
        description.repeats = repeats;
        description.wait = wait;
        description.img = imagepath;
        description.message = "is this correct element ? if is then it was found correctly";
        fnPushToOutputArray(description)

        return found;

    })
    return init();
}

Answer 2

你应该将一个String传递给Error对象，所以如果你想交换一个对象，你可以使用JSON.stringify()这样：

try {
  throw new Error(JSON.stringify({result:"Hello, World"}));
}
catch(error) {
  console.log(JSON.parse(error.message))
}

正如您所看到的，这是您通过抛出错误将数据从try发送到catch的方式。你可以使捕获方式的第二部分更短：

error = JSON.parse(error.message);

如何错误地传递变量

2 个答案: