blocks|key|16210|text|在遍历列表时不需要回调函数。只需在循环之后添加end()调用即可。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|16211|posts.forEach(function(v,+i){
+++res.write(v+%2B+".+Index+"+%2B+i);
});
res.end();|code-block|syntax|javascript|16212|entityMap^0|N|5|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|P|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|Q|8|@]|D|@]|E|$]]]|L|$]]

<p>You shouldn't need a callback for iterating through a list. Just add the <code>end()</code> call after the loop.</p>

<pre><code>posts.forEach(function(v, i){
   res.write(v + ". Index " + i);
});
res.end();
</code></pre>


blocks|key|232566|text|如果你遇到异步函数，并且你想确保在执行代码之前它完成了它的任务，我们总是可以使用回调功能。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|232567|例如：|232568|var+ctr+=+0;
posts.forEach(function(element,+index,+array){
++++asynchronous(function(data){
+++++++++ctr%2B%2B;+
+++++++++if+(ctr+===+array.length)+{
+++++++++++++functionAfterForEach();
+++++++++}
++++})
});|code-block|syntax|javascript|232569|注意：functionAfterForEach是在foreach任务完成后执行的函数。asynchronous是在foreach内部执行的异步函数。|offset|length|style|CODE|232570|entityMap^0|0|0|0|3|K|17|C|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|R|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|S|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|T|8|@$K|U|L|V|M|N]|$K|W|L|X|M|N]]|9|@]|A|$]]|$1|O|3|-4|5|6|7|Y|8|@]|9|@]|A|$]]]|P|$]]

<p>If you encounter asynchronous functions, and you want to make sure that before executing the code it finishes its task, we can always use the callback capability.</p>

<p>For example:</p>

<pre><code>var ctr = 0;
posts.forEach(function(element, index, array){
    asynchronous(function(data){
         ctr++; 
         if (ctr === array.length) {
             functionAfterForEach();
         }
    })
});
</code></pre>

<p>Note: <code>functionAfterForEach</code> is the function to be executed after foreach tasks are finished.  <code>asynchronous</code> is the asynchronous function executed inside foreach.</p>


blocks|key|232591|text|这就是异步Node.js的解决方案。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|232592|使用异步npm包。|232593|(JavaScript)+Synchronizing+forEach+Loop+with+callbacks+inside|offset|length|232594|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/questions/15162049/javascript-synchronizing-foreach-loop-with-callbacks-inside^0|0|0|0|1P|0|0^^$0|@$1|2|3|4|5|6|7|P|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|Q|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|R|8|@]|9|@$F|S|G|T|1|U]]|A|$]]|$1|H|3|-4|5|6|7|V|8|@]|9|@]|A|$]]]|I|$J|$5|K|L|M|A|$N|O]]]]

<p>This is the solution for Node.js which is asynchronous. </p>

<p>using the async npm package.</p>

<p><a href="https://stackoverflow.com/questions/15162049/javascript-synchronizing-foreach-loop-with-callbacks-inside">(JavaScript) Synchronizing forEach Loop with callbacks inside</a></p>


blocks|key|16276|text|我希望这能解决你的问题，当我需要执行带有异步任务的forEach时，我通常会用到它。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|16277|foo+=+[a,b,c,d];
waiting+=+foo.length;
foo.forEach(function(entry){
++++++doAsynchronousFunction(entry,finish)+//call+finish+after+each+entry
}
function+finish(){
++++++waiting--;
++++++if+(waiting==0)+{
++++++++++//do+your+Job+intended+to+be+done+after+forEach+is+completed
++++++}+
}|code-block|syntax|javascript|16278|使用|16279|function+doAsynchronousFunction(entry,callback){
+++++++//asynchronousjob+with+entry
+++++++callback();
}|16280|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

<p>Hope this will fix your problem, i usually work with this when i need to execute forEach with asynchronous tasks inside.</p>

<pre><code>foo = [a,b,c,d];
waiting = foo.length;
foo.forEach(function(entry){
      doAsynchronousFunction(entry,finish) //call finish after each entry
}
function finish(){
      waiting--;
      if (waiting==0) {
          //do your Job intended to be done after forEach is completed
      } 
}
</code></pre>

<p>with </p>

<pre><code>function doAsynchronousFunction(entry,callback){
       //asynchronousjob with entry
       callback();
}
</code></pre>


blocks|key|232623|text|我的解决方案是：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|232624|//Object+forEachDone

Object.defineProperty(Array.prototype,+"forEachDone",+{
++++enumerable:+false,
++++value:+function(task,+cb){
++++++++var+counter+=+0;
++++++++this.forEach(function(item,+index,+array){
++++++++++++task(item,+index,+array);
++++++++++++if(array.length+===+%2B%2Bcounter){
++++++++++++++++if(cb)+cb();
++++++++++++}
++++++++});
++++}
});


//Array+forEachDone

Object.defineProperty(Object.prototype,+"forEachDone",+{
++++enumerable:+false,
++++value:+function(task,+cb){
++++++++var+obj+=+this;
++++++++var+counter+=+0;
++++++++Object.keys(obj).forEach(function(key,+index,+array){
++++++++++++task(obj[key],+key,+obj);
++++++++++++if(array.length+===+%2B%2Bcounter){
++++++++++++++++if(cb)+cb();
++++++++++++}
++++++++});
++++}
});|code-block|syntax|javascript|232625|示例：|232626|var+arr+=+['a',+'b',+'c'];

arr.forEachDone(function(item){
++++console.log(item);
},+function(){
+++console.log('done');
});

//+out:+a+b+c+done|232627|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

<p>My solution:</p>

<pre class="lang-js prettyprint-override"><code>//Object forEachDone

Object.defineProperty(Array.prototype, "forEachDone", {
    enumerable: false,
    value: function(task, cb){
        var counter = 0;
        this.forEach(function(item, index, array){
            task(item, index, array);
            if(array.length === ++counter){
                if(cb) cb();
            }
        });
    }
});


//Array forEachDone

Object.defineProperty(Object.prototype, "forEachDone", {
    enumerable: false,
    value: function(task, cb){
        var obj = this;
        var counter = 0;
        Object.keys(obj).forEach(function(key, index, array){
            task(obj[key], key, obj);
            if(array.length === ++counter){
                if(cb) cb();
            }
        });
    }
});
</code></pre>

<p>Example:</p>

<pre class="lang-js prettyprint-override"><code>var arr = ['a', 'b', 'c'];

arr.forEachDone(function(item){
    console.log(item);
}, function(){
   console.log('done');
});

// out: a b c done
</code></pre>


blocks|key|16310|text|setInterval如何，检查完整的迭代计数，带来保证。虽然我不确定它是否会使作用域超载，但我使用它，似乎就是它|type|unstyled|depth|inlineStyleRanges|entityRanges|data|16311|_.forEach(actual_JSON,+function+(key,+value)+{

+++++//+run+any+action+and+push+with+each+iteration+

+++++array.push(response.id)

});


setInterval(function(){

++++if(array.length+>+300)+{

++++++++callback()

++++}

},+100);|code-block|syntax|javascript|16312|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

<p>How about setInterval, to check for complete iteration count, brings guarantee. not sure if it won't overload the scope though but I use it and seems to be the one</p>

<pre><code>_.forEach(actual_JSON, function (key, value) {

     // run any action and push with each iteration 

     array.push(response.id)

});


setInterval(function(){

    if(array.length &gt; 300) {

        callback()

    }

}, 100);
</code></pre>


blocks|key|232703|text|My+solution+without+Promise+(这将确保每个操作在下一个操作开始之前结束)：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|232704|​|232705|Array.prototype.forEachAsync+=+function+(callback,+end)+{
++++++++var+self+=+this;
++++
++++++++function+task(index)+{
++++++++++++var+x+=+self[index];
++++++++++++if+(index+>=+self.length)+{
++++++++++++++++end()
++++++++++++}
++++++++++++else+{
++++++++++++++++callback(self[index],+index,+self,+function+()+{
++++++++++++++++++++task(index+%2B+1);
++++++++++++++++});
++++++++++++}
++++++++}
++++
++++++++task(0);
++++};
++++
++++
++++var+i+=+0;
++++var+myArray+=+Array.apply(null,+Array(10)).map(function(item)+{+return+i%2B%2B;+});
++++console.log(JSON.stringify(myArray));
++++myArray.forEachAsync(function(item,+index,+arr,+next){
++++++setTimeout(function(){
++++++++$(".toto").append("<div>item+index+"+%2B+item+%2B+"+done</div>");
++++++++console.log("action+"+%2B+item+%2B+"+done");
++++++++next();
++++++},+300);
++++},+function(){
++++++++$(".toto").append("<div>ALL+ACTIONS+ARE+DONE</div>");
++++++++console.log("ALL+ACTIONS+ARE+DONE");
++++});|code-block|syntax|javascript|232706|<script+src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div+class="toto">

</div>|232707|232708|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|N|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|O|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|P|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|F|7|Q|8|@]|9|@]|A|$G|H]]|$1|K|3|C|5|6|7|R|8|@]|9|@]|A|$]]|$1|L|3|-4|5|6|7|S|8|@]|9|@]|A|$]]]|M|$]]

<p>My solution without Promise (this ensures that every action is ended before the next one begins):</p>

<p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
<div class="snippet-code">
<pre class="snippet-code-js lang-js prettyprint-override"><code>Array.prototype.forEachAsync = function (callback, end) {
        var self = this;
    
        function task(index) {
            var x = self[index];
            if (index &gt;= self.length) {
                end()
            }
            else {
                callback(self[index], index, self, function () {
                    task(index + 1);
                });
            }
        }
    
        task(0);
    };
    
    
    var i = 0;
    var myArray = Array.apply(null, Array(10)).map(function(item) { return i++; });
    console.log(JSON.stringify(myArray));
    myArray.forEachAsync(function(item, index, arr, next){
      setTimeout(function(){
        $(".toto").append("&lt;div&gt;item index " + item + " done&lt;/div&gt;");
        console.log("action " + item + " done");
        next();
      }, 300);
    }, function(){
        $(".toto").append("&lt;div&gt;ALL ACTIONS ARE DONE&lt;/div&gt;");
        console.log("ALL ACTIONS ARE DONE");
    });</code></pre>
<pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"&gt;&lt;/script&gt;
&lt;div class="toto"&gt;

&lt;/div&gt;</code></pre>
</div>
</div>
</p>


blocks|key|232749|text|我试着用一种简单的方法来解决它，与你分享：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|232750|let+counter+=+0;
++++++++++++arr.forEach(async+(item,+index)+=>+{
++++++++++++++++await+request.query(item,+(err,+recordset)+=>+{
++++++++++++++++++++if+(err)+console.log(err);

++++++++++++++++++++//do+Somthings

++++++++++++++++++++counter%2B%2B;
++++++++++++++++++++if(counter+==+tableCmd.length){
++++++++++++++++++++++++sql.close();
++++++++++++++++++++++++callback();
++++++++++++++++++++}
++++++++++++++++});|code-block|syntax|javascript|232751|request是Node+js中mssql+Library的函数。这可以替换你想要的每个函数或代码。GoodLuck|offset|length|style|CODE|232752|entityMap^0|0|0|0|7|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@$I|R|J|S|K|L]]|9|@]|A|$]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

<p>I try Easy Way to resolve it, share it with you :</p>

<pre><code>let counter = 0;
            arr.forEach(async (item, index) =&gt; {
                await request.query(item, (err, recordset) =&gt; {
                    if (err) console.log(err);

                    //do Somthings

                    counter++;
                    if(counter == tableCmd.length){
                        sql.close();
                        callback();
                    }
                });
</code></pre>

<p><code>request</code> is Function of mssql Library in Node js. This can replace each function or Code u want.
GoodLuck</p>


blocks|key|16396|text|var+i=0;
const+waitFor+=+(ms)+=>+
{+
++new+Promise((r)+=>+
++{
+++setTimeout(function+()+{
+++console.log('timeout+completed:+',ms,'+:+',i);+
+++++i%2B%2B;
+++++if(i==data.length){
++++++console.log('Done')++
++++}
++},+ms);+
+})
}
var+data=[1000,+200,+500];
data.forEach((num)+=>+{
++waitFor(num)
})|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|16397|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>var i=0;
const waitFor = (ms) =&gt; 
{ 
  new Promise((r) =&gt; 
  {
   setTimeout(function () {
   console.log('timeout completed: ',ms,' : ',i); 
     i++;
     if(i==data.length){
      console.log('Done')  
    }
  }, ms); 
 })
}
var data=[1000, 200, 500];
data.forEach((num) =&gt; {
  waitFor(num)
})
</code></pre>


blocks|key|16417|text|在ES2018中，你可以使用异步迭代器：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|16418|const+asyncFunction+=+a+=>+fetch(a);
const+itemDone+=+a+=>+console.log(a);

async+function+example()+{
++const+arrayOfFetchPromises+=+[1,+2,+3].map(asyncFunction);

++for+await+(const+item+of+arrayOfFetchPromises)+{
++++itemDone(item);
++}

++console.log('All+done');
}|code-block|syntax|javascript|16419|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

<p>With ES2018 you can use async iterators:</p>

<pre><code>const asyncFunction = a =&gt; fetch(a);
const itemDone = a =&gt; console.log(a);

async function example() {
  const arrayOfFetchPromises = [1, 2, 3].map(asyncFunction);

  for await (const item of arrayOfFetchPromises) {
    itemDone(item);
  }

  console.log('All done');
}
</code></pre>


blocks|key|16421|text|+var+counter+=+0;
+var+listArray+=+[0,+1,+2,+3,+4];
+function+callBack()+{
+++++if+(listArray.length+===+counter)+{
+++++++++console.log('All+Done')
+++++}
+};
+listArray.forEach(function(element){
+++++console.log(element);
+++++counter+=+counter+%2B+1;
+++++callBack();
+});|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|16422|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code> var counter = 0;
 var listArray = [0, 1, 2, 3, 4];
 function callBack() {
     if (listArray.length === counter) {
         console.log('All Done')
     }
 };
 listArray.forEach(function(element){
     console.log(element);
     counter = counter + 1;
     callBack();
 });
</code></pre>


<p>As the title suggests. How do I do this? </p>

<p>I want to call <code>whenAllDone()</code> after the forEach-loop has gone through each element and done some asynchronous processing.</p>

<pre><code>[1, 2, 3].forEach(
  function(item, index, array, done) {
     asyncFunction(item, function itemDone() {
       console.log(item + " done");
       done();
     });
  }, function allDone() {
     console.log("All done");
     whenAllDone();
  }
);
</code></pre>

<p>Possible to get it to work like this? When the second argument to forEach is a callback function which runs once it went through all iterations?</p>

<p>Expected output:</p>

<pre><code>3 done
1 done
2 done
All done!
</code></pre>


Callback after all asynchronous forEach callbacks are completed

JSON

正如标题所暗示的那样。我该怎么做呢？我希望在forEach循环遍历每个元素并完成一些异步处理之后调用whenAllDone()。[1, 2, 3].forEach(  function(item, index, array, done) {     asyncFunction(item, function itemDo...

问所有异步forEach回调完成后的回调
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