删除嵌套的承诺

删除嵌套的承诺

在每个

then

回调中，您都需要 返回 新的Promise：

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

.then()

调用返回的承诺然后将使用“内部”承诺中的值进行解析，以便您可以轻松地链接它们。

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