如何在函数内的async.eachSeries循环内从多个get请求返回响应

I am attempting to return a new array, created by combining arrays from several get requests. The new array returns correctly within the async.eachSeries async library function, however the parent function returns undefined.

我试图返回一个新的数组,通过组合来自几个get请求的数组创建。新数组在async.eachSeries异步库函数中正确返回,但父函数返回undefined。

My understanding is that the return within the parent function is running synchronously with the async.eachSeries() (before it can finish), which causes the parent function to return undefined.

我的理解是,父函数内的返回与async.eachSeries()同步运行(在它完成之前),这会导致父函数返回undefined。

var array_strings = [ “someUrl”, “someUrl”, “someUrl” ]

function get_forEachUrlString(base_url, array_strings) {
    …
    var combinedArray = [];
    var mergedArray = [];
    …
    async.eachSeries(array_strings, function(item, done) {
        …
        $.get(bas_url+item, function(data) {
            …
            combinedArray.push(data)
            done(); // stopping the async looping
            mergedArray = [].concat.apply([], combinedArray); // Merging the array of combined arrays
        });
    }, function(err) {
        if (err) {
            throw err;
        }
        console.log("All requests are done");
        console.log(mergedArray); // logs correct array
        return mergedArray
    });
    console.log(mergedArray); // logs [] empty array
    return mergedArray // Hoping this would return the newly created mergedArray
}

get_forEachUrlString(“someBaseUrl”, array_strings) // Attempting to return mergedArray

// this function tries to call the mergedArray, but returns undefined
function initialRender() {
    …
    console.log(merged) // returns undefined
}

I have been searching for a way to get the parent function get_forEachUrlString() to return the value produced by the async.eachSeries function. I believe I will need to run a callback, but after trying several different combinations I’m still stumped.

我一直在寻找一种方法来获取父函数get_forEachUrlString()来返回async.eachSeries函数产生的值。我相信我需要进行回调,但在尝试了几种不同的组合后,我仍然难倒。

How can I get the new array I’ve created, mergedArray to return from the function get_forEachUrlString()?

如何获取我创建的新数组,mergedArray从函数get_forEachUrlString()返回?

EDIT: I failed to mention that I am attempting to call the returned value from get_forEachUrlString() within initialRender(). See how I fixed this in my answer below.

编辑:我没有提到我试图在initialRender()中调用get_forEachUrlString()返回的值。请参阅下面的答案,了解我如何修复此问题。

1 个解决方案

#1

After some trial and error I was able to get this working. I was attempting to place any number of callbacks, but what I really needed to do was place the initialRender() function within the get_forEachUrlString() function and pass the new mergedArray value to the initialRender() function.

经过一些试验和错误,我能够使这个工作。我试图放置任意数量的回调,但我真正需要做的是将initialRender()函数放在get_forEachUrlString()函数中,并将新的mergedArray值传递给initialRender()函数。

So the proper setup looks like this.

所以正确的设置看起来像这样。

function get_forEachUrlString(base_url, array_strings) {
    …
    async.eachSeries(array_strings, function(item, done) {
        …
    }, function(err) {
        …
        mergedArray = [].concat.apply([], combinedArray);
        initialRender(mergedArray);
    });
}

get_forEachUrlString(“someBaseUrl”, array_strings)

Then the initialRender() returns what it should.

然后initialRender()返回它应该的内容。

#1