在forEach内部进行异步调用 [英] make async call inside forEach

问题描述

我正在尝试遍历对象数组，并使用Node.js中的异步功能在这些对象内添加一些东西.

I am trying to iterate thru array of objects and add some stuff inside these objects using async function in Node.js.

到目前为止，我的代码如下:

So far my code looks like:

var channel = channels.related('channels');
channel.forEach(function (entry) {

    knex('albums')
        .select(knex.raw('count(id) as album_count'))
        .where('channel_id', entry.id)
        .then(function (terms) {
            var count = terms[0].album_count;
            entry.attributes["totalAlbums"] = count;
        });

});
//console.log("I want this to be printed once the foreach is finished");
//res.json({error: false, status: 200, data: channel});

如何在JavaScript中实现这种目标?

How can I achieve such a thing in JavaScript?

推荐答案

使用 async.each

async.each(channel, function(entry, next) {
    knex('albums')
         .select(knex.raw('count(id) as album_count'))
         .where('channel_id', entry.id)
         .then(function (terms) {
            var count = terms[0].album_count;
            entry.attributes["totalAlbums"] = count;
            next();
         });
}, function(err) {
    console.log("I want this to be printed once the foreach is finished");
    res.json({error: false, status: 200, data: channel});
});

处理完所有条目后，将调用最终回调.

The final callback will be called when all entries are processed.

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