Question

我对NodeJS中的承诺有疑问，甚至认为我使用的是Bluebird。在以下代码中：

var Promise = require('bluebird');
var google = require('utils/google');

// list of (max 60 * number of types defined) nearby places
var nearby_places = [];

Promise.each(config.type.nearby, function (type) {
    google.nearbySearch(request.query.lat, request.query.lng, request.query.rad, type)
        .then(function (places) {

            // list of (max 60) places
            var detailed_places = [];

            console.log('Found ' + places.length + ' places.');

            // Get full details of places and insert them into database
            Promise.each(places, function (place_id) {
                google.getPlaceDetails(place_id)
                    .then(function (res) {
                        detailed_places.push(res);
                    })
                    .catch(function (err) {
                        console.log(err);
                    });
                })
                .then(function () {
                    // Push detailed places to nearby places
                    nearby_places = nearby_places.concat(detailed_places);
                });

             })
             .catch(function (err) {
                 console.log(err);
             });
        }).then(function () {
            // Returns (max 60 * number of types defined) nearby places
            return reply(nearby_places);
        });

执行google.nearbySearch()并在那里打印一些东西，所以我知道它在运行。但是当它结束时，它不会等待内部Promise.each(places, ...。它直接转到return reply(...，nearby_places为空。然后，它会在控制台Found X places.中显示我。

我不认为我完全理解Promises / Bluebird，但我不知道我做错了什么。

Answer 1

问题在于，return Promise .then()并非google.nearbySearch(request.query.lat, request.query.lng, request.query.rad, type)链接到Promise.each(places, function(){})。

您应该可以通过从.then()链接到google.nearbySearch(request.query.lat, request.query.lng, request.query.rad, type)来电{1}来回复return Promise.each(places, function(){})来解决问题

using namespace <your_library_namespace>;

在NodeJS中的promisified cicle内的promisified cicle

1 个答案: