使用mongodb和nodejs解决承诺 [英] resolving a promise using mongodb and nodejs
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问题描述
你好,我是nodejs和mongodb的新手,在解决第二个承诺后,我无法解决我的第一个承诺.解决后,我可以看到第二个承诺的结果.这是我的代码
Hello I am new to nodejs and mongodb, i am having trouble resolving my first promise after the second promise has been resolved. I can see the result of my second promise after it is resolved. Here is my code
var getShows = function () {
return new Promise(function (resolve, reject) {
usersdb.find(function (err, result) {
if(err) return console.error(err);
var usersFromCall = result;
var task = function (users) {
return new Promise(function (resolve, reject) {
var user = {
'name': '',
'pages': []
}
user.name = users.show;
console.log(users);
pagedb.find({'show' : user.name}, function (err, resp) {
for(var j = 0 ; j <resp.length; j ++){
var pages = { 'pageId': ''};
pages.pageId = resp[j].pageId;
user.pages.push(pages);
}
console.log(user);
resolve({show: user});
})
});
};
var actions = usersFromCall.map(task);
return Promise.all(actions);
}).then(function () {
resolve()
})
});
};
我在找到之后在then函数中解析第一个诺言吗?
do i resolve the first promise in a then function after the find?
推荐答案
以下方法应该起作用:
var getShows = function () {
return new Promise(function (resolve, reject) {
usersdb.find(function (err, users) {
if (err) return console.error(err);
var task = function (user) {
return new Promise(/* ... */);
};
var actions = users.map(task);
Promise.all(actions).then(resolve, reject);
});
});
};
getShows().then(function (results) {
// Prints the result of each task as an array
console.log(results);
});
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