"A promise was created in a handler but was not returned from it"

Question

当用户单击按钮 (#lfdsubmit) 时，它会调用应该 return 承诺的函数 (LFD_SearchContainer())。但是错误发生在

LFD_SearchContainer('EISU1870725')
.then(container => {
  ST2.db2(container);
})

怎么了？代码：（不要完全相信注释掉的部分会指导您完成这段代码——我忘记更新其中的一些）

函数 LFDTrack () {

function LFD_SearchContainer (requestedContainer) {
    return new Promise((resolve, reject) => {
        let lfd_scanparams = { TableName: 'lfd_table1' }
        db.scan(lfd_scanparams, (err, containers) => {
            if (err) {
                reject(err);
            } else {
                containers = containers.Items;

                let requestedContainers = []; // different variable than arg

                let containerObject; // this will be the resolved object

                // this will return the object of the searched container
                let findIt = _.forEach(containers, container => {
                    if (container.container === requestedContainer) {
                        containerObject = container;
                    }
                });
                containerObject = findIt[0];
                //console.log(findIt[0]);
                resolve(containerObject.container);
            }
        });
    });
}

$(function() {
    $("#lfdsubmit").click(function (e) {
        e.preventDefault();

        let lsd_modaltitle = $("#lfdmodaltitle");
        let lsd_modalcontent = $("#lfdmodalcontent");

        LFD_SearchContainer('EISU1870725')
        .then(container => { 
            ST2.db2(container); // will send the object
        })
        .catch(error => {
            console.log(error);
        });
    });
});

}

Answer 1

如果 ST2.db2(container); returns 一个承诺，您需要将该行更改为

return ST2.db2(container);

如果没有，你可以把return null;放在后面，像这样：

ST2.db2(container);
return null;

由于您没有提供 ST2 的定义，我不知道 db2 方法 returns 是否是一个承诺。 :)

错误由bluebird作者解释here。

"A promise was created in a handler but was not returned from it"

"A promise was created in a handler but was not returned from it"

javascript

promise

bluebird