javascript – 删除嵌套承诺

我是新来的承诺和编写一些网络代码使用请求和承诺在NodeJS.

我想删除这些嵌套的承诺,并链接它们,但我不知道我会如何去做/是否是正确的方法.

exports.viewFile = function(req,res) {
var fileId = req.params.id;
BoxContentRequest('files/' + fileId + '/content',req.user.Box.accessToken)
    .then(function(response) {
        BoxViewerRequest('documents',{url: response.request.href},'POST')
            .then(function(response) {
                BoxViewerRequest('sessions',{document_id: response.body.id},'POST')
                    .then(function(response) {
                        console.log(response);
                    });
            });
    });

};

这是请求代码：

var baseContentURL = 'https://api.Box.com/2.0/';
var baseViewerURL = 'https://view-api.Box.com/1/';

function BoxContentRequest(url,accessToken) {
    return new Promise(function (resolve,reject) {
            var options = {
                url: baseContentURL + url,headers: {
                    Authorization: 'Bearer ' + accessToken,}
            };
      request(options,function (err,res) {
        if (err) {
          return reject(err);
        } else if (res.statusCode !== 200) {
          err = new Error("Unexpected status code: " + res.statusCode);
          err.res = res;
          return reject(err);
        }
        resolve(res);
      });
    });
}

function BoxViewerRequest(url,body,method) {
    return new Promise(function (resolve,reject) {
            var options = {
                method: method,url: baseViewerURL + url,headers: {
                    Authorization: 'Token ' + config.Box.viewerApiKey
                },json: body
            };
      request(options,res,body) {
        if (err) {
          return reject(err);
        } else if (res.statusCode !== 200 && res.statusCode !== 201 && res.statusCode !== 202) {
          err = new Error("Unexpected status code: " + res.statusCode);
          err.res = res;
          return reject(err);
        }
        resolve(res,body);
      });
    });
}

任何见解将不胜感激.

解决方法

从每一个回调,你将需要返回新的承诺：

exports.viewFile = function(req,res) {
    var fileId = req.params.id;
    BoxContentRequest('files/' + fileId + '/content',req.user.Box.accessToken)
      .then(function(response) {
          return BoxViewerRequest('documents','POST');
      })
      .then(function(response) {
          return BoxViewerRequest('sessions','POST');
      })
      .then(function(response) {
          console.log(response);
      });
};

然后由.then()调用返回的承诺将随着“内部”承诺中的值解析,以便您轻松链接它们.

通用模式：

somePromise.then(function(r1) {
    return nextPromise.then(function(r2) {
        return anyValue;
    });
}) // resolves with anyValue

     ||
    \||/
     \/

somePromise.then(function(r1) {
    return nextPromise;
}).then(function(r2) {
    return anyValue;
}) // resolves with anyValue as well

javascript – 删除嵌套承诺

解决方法

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