blocks|key|316595|text|您可以使用node-sync+lib来完成此操作|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|316596|var+sync+=+require('sync');

sync(function(){
++var+result+=+query.sync(query,+params);
++//+result+can+be+used+immediately
})|code-block|syntax|javascript|316597|注意:您的查询必须使用标准回调调用(错误优先)：callback(+error，result)。如果不能更改查询方法，只需创建.async()包装器(参见github链接)。|316598|entityMap|0|LINK|mutability|MUTABLE|url|https://github.com/0ctave/node-sync^0|5|D|0|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@$A|T|B|U|1|V]]|C|$]]|$1|D|3|E|5|F|7|W|8|@]|9|@]|C|$G|H]]|$1|I|3|J|5|6|7|X|8|@]|9|@]|C|$]]|$1|K|3|-4|5|6|7|Y|8|@]|9|@]|C|$]]]|L|$M|$5|N|O|P|C|$Q|R]]]]

You can do it with <a href="https://github.com/0ctave/node-sync" rel="noreferrer">node-sync lib</a>

<pre><code>var sync = require('sync');

sync(function(){
 var result = query.sync(query, params);
 // result can be used immediately
})
</code></pre>

Notice: your query must use standart callback call (with error first): callback(error, result).
If you can't change query method, just create .async() wrapper (see github link).

blocks|key|99707|text|我一直在使用syncrhonize.js，取得了巨大的成功。甚至还有一个挂起的拉取请求(它工作得很好)，以支持具有多个参数的异步函数。比node-sync+imho更好更容易使用。增加了额外的好处，它有易于理解和全面的文档，而节点同步没有。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|99708|entityMap|0|LINK|mutability|MUTABLE|url|http://alexeypetrushin.github.io/synchronize/docs/index.html^0|6|E|0|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@$A|M|B|N|1|O]]|C|$]]|$1|D|3|-4|5|6|7|P|8|@]|9|@]|C|$]]]|E|$F|$5|G|H|I|C|$J|K]]]]

I've been using <a href="http://alexeypetrushin.github.io/synchronize/docs/index.html" rel="nofollow">syncrhonize.js</a> with great success. There's even a pending pull request (which works quite well) to support async functions which have multiple parameters. Far better and easier to use than node-sync imho. Added bonus that it has easy-to-understand and thorough documentation, whereas node-sync does not.

blocks|key|99760|text|你遇到的问题是你的紧凑的while循环阻塞了。所以我认为你的查询回调永远不会运行。我认为你需要使用setTimeout或类似的东西来防止函数阻塞，但如果你这样做了，函数将在回调被调用之前返回。此功能必须在较低级别上实现。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|99761|如果您在浏览器中，您可以查看this+article。在node中，您必须依赖于您要查询的任何内容的实现。它可能提供也可能不提供同步方法。|offset|length|99762|entityMap|0|LINK|mutability|MUTABLE|url|https://developer.mozilla.org/en-US/docs/Web/API/XMLHttpRequest/Synchronous_and_Asynchronous_Requests^0|0|E|C|0|0^^$0|@$1|2|3|4|5|6|7|N|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|O|8|@]|9|@$D|P|E|Q|1|R]]|A|$]]|$1|F|3|-4|5|6|7|S|8|@]|9|@]|A|$]]]|G|$H|$5|I|J|K|A|$L|M]]]]

The issue you are having is that your tight while loop is blocking. So I don't think your query callback will ever be run. I think you need to use setTimeout or the like to prevent the function from blocking, but should you do so, the function will return before the callback is called. This functionality must be implemented at a lower level.

If you are in the browser, you might check out <a href="https://developer.mozilla.org/en-US/docs/Web/API/XMLHttpRequest/Synchronous_and_Asynchronous_Requests" rel="nofollow">this article</a>. In node you have to rely on the implementation of whatever you're querying. It may or may not provide synchronous methods.

blocks|key|316842|text|使用deasync+-一个用C%2B%2B编写的模块，它将Node.js事件循环暴露给JavaScript。该模块还公开了一个sleep函数，该函数会阻塞后续代码，但不会阻塞整个线程，也不会引起繁忙的等待。您可以将sleep函数放在while循环中：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|316843|var+asyncToSync+=+syncFunc();

function+syncFunc()+{
++++var+sync+=+true;
++++var+data+=+null;
++++query(params,+function(result){
++++++++data+=+result;
++++++++sync+=+false;
++++});
++++while(sync)+{require('deasync').sleep(100);}
++++return+data;
}|code-block|syntax|javascript|316844|entityMap|0|LINK|mutability|MUTABLE|url|https://github.com/abbr/deasync^0|1N|5|2V|5|34|5|2|7|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@$9|T|A|U|B|C]|$9|V|A|W|B|C]|$9|X|A|Y|B|C]]|D|@$9|Z|A|10|1|11]]|E|$]]|$1|F|3|G|5|H|7|12|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|13|8|@]|D|@]|E|$]]]|L|$M|$5|N|O|P|E|$Q|R]]]]

Use <a href="https://github.com/abbr/deasync" rel="noreferrer">deasync</a> - a module written in C++ which exposes Node.js event loop to JavaScript. The module also exposes a <code>sleep</code> function that blocks subsequent code but doesn't block entire thread, nor incur busy wait. You can put the <code>sleep</code> function in your <code>while</code> loop:

<pre><code>var asyncToSync = syncFunc();

function syncFunc() {
 var sync = true;
 var data = null;
 query(params, function(result){
 data = result;
 sync = false;
 });
 while(sync) {require('deasync').sleep(100);}
 return data;
}
</code></pre>

blocks|key|99878|text|现在，这种生成器模式在许多情况下都是一个很好的解决方案：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|99879|//+nodejs+script+doing+sequential+prompts+using+async+readline.question+function

var+main+=+(function*+()+{

++//+just+import+and+initialize+'readline'+in+nodejs
++var+r+=+require('readline')
++var+rl+=+r.createInterface({input:+process.stdin,+output:+process.stdout+})

++//+magic+here,+the+callback+is+the+iterator.next
++var+answerA+=+yield+rl.question('do+you+want+this?+',+res=>main.next(res))++++

++//+and+again,+in+a+sync+fashion
++var+answerB+=+yield+rl.question('are+you+sure?+',+res=>main.next(res))++++++++

++//+readline+boilerplate
++rl.close()

++console.log(answerA,+answerB)

})()++++//+<--+executed:+iterator+created+from+generator
main.next()+++++//+kick+off+the+iterator,+
++++++++++++++++//+runs+until+the+first+'yield',+including+rightmost+code
++++++++++++++++//+and+waits+until+another+main.next()+happens|code-block|syntax|javascript|99880|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|$]]

Nowadays this generator pattern can be a fantastic solution in many situations:

<pre><code>// nodejs script doing sequential prompts using async readline.question function

var main = (function* () {

 // just import and initialize 'readline' in nodejs
 var r = require('readline')
 var rl = r.createInterface({input: process.stdin, output: process.stdout })

 // magic here, the callback is the iterator.next
 var answerA = yield rl.question('do you want this? ', res=&gt;main.next(res)) 

 // and again, in a sync fashion
 var answerB = yield rl.question('are you sure? ', res=&gt;main.next(res)) 

 // readline boilerplate
 rl.close()

 console.log(answerA, answerB)

})() // &lt;-- executed: iterator created from generator
main.next() // kick off the iterator, 
 // runs until the first 'yield', including rightmost code
 // and waits until another main.next() happens
</code></pre>

How can I make this work

<pre><code>var asyncToSync = syncFunc();

function syncFunc() {
 var sync = true;
 var data = null;
 query(params, function(result){
 data = result;
 sync = false;
 });
 while(sync) {}
 return data;
}
</code></pre>

I tried to get sync function from async one, 
I need it to use FreeTds async query as sync one

Node.js async to sync

我怎么才能让它工作呢？var asyncToSync = syncFunc();function syncFunc() {    var sync = true;    var data = null;    query(params, function(result){        data = result;  ...

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