我的代码中出现未处理的拒绝错误,但跟踪不会告诉我导致该错误的原因。我认为这是webp.cwebp
导致问题的电话。当我运行代码时,我成功转换了图像和日志状态,然后遇到了未处理的拒绝。貌似我没有进入最后两个.then(()
阻塞,因为没有控制台消息被记录。
如何正确处理拒绝错误以避免出现此错误?我尝试过插入和删除status
in the resolve()
and reject()
声明,但似乎并没有解决它。
// Download image file from Google Cloud Storage bucket.
return file.download({ destination: tempLocalFilename })
.catch((err) => {
console.error('Failed to download file.', err);
return Promise.reject(err);
})
.then(() => {
console.log(`Image ${file.name} has been downloaded to ${tempLocalFilename}.`);
// Convert PNG to webp using webp-converter.
return new Promise( (resolve, reject) => {
webp.cwebp(tempLocalFilename, newLocalFilename, "-q 80", status => {
console.log(status);
if (status === '100') {
resolve();
} else {
reject(status);
}
}
);
});
})
.then(() => {
console.log(`Image ${file.name} has been converted.`);
// Upload the converted image back into the bucket.
return file.bucket.upload(newLocalFilename, { destination: file.name })
.catch((err) => {
console.error('Failed to upload converted image.', err);
return Promise.reject(err);
});
})
.then(() => {
console.log(`Converted image has been uploaded to ${file.name}`);
// Delete the temporary file.
return new Promise((resolve, reject) => {
fs.unlink(tempLocalFilename, (err) => {
if (err) {
reject(err);
} else {
resolve();
}
});
});
});
Q:我收到未处理的拒绝错误,如何正确处理拒绝错误?
A:就像评论已经说过的那样,.catch(...)
将阻止你的异常冒泡成为unhandled rejection error
.
或者,您也可以为每个插入拒绝处理程序函数.then(...)
条款。也就是说,对于每个.then()
它应该有两个函数,一个用于快乐路径,另一个用于糟糕路径。
E.g.
return new Promise( (resolve, reject) => {
webp.cwebp(tempLocalFilename, newLocalFilename, "-q 80", status => {
...
}
);
});
})
.then(/*happy path=*/() => {
console.log(`Image ${file.name} has been converted.`);
// Upload the converted image back into the bucket.
return file.bucket.upload(newLocalFilename, { destination: file.name })
.catch((err) => {
console.error('Failed to upload converted image.', err);
return Promise.reject(err);
});
},
/*unhappy path=*/ (error) => {
console.log("oops something went wrong during uploading");
})
/*catch all rejection=*/
.catch(error => {
console.log("something bad happened somewhere, rollback!");
});
本文内容由网友自发贡献,版权归原作者所有,本站不承担相应法律责任。如您发现有涉嫌抄袭侵权的内容,请联系:hwhale#tublm.com(使用前将#替换为@)