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copied!<p>From your comment on Quentin's answer</p> <blockquote> <p>How to create a function which has some manipulation inside it which is a normal synchronous function but the overall flow doesn't wait for this function to complete rather moves to the next function.</p> </blockquote> <p>JavaScript, the language, doesn't have a feature to do that. So you look to the environment in which it's running to see if the environment has that feature.</p> <p>NodeJS does. In fact, it has several of them: <a href="http://nodejs.org/api/all.html#all_settimeout_callback_delay_arg" rel="nofollow noreferrer"><code>setTimeout</code></a> (which is a bit like what browsers give you), <a href="http://nodejs.org/api/all.html#all_setimmediate_callback_arg" rel="nofollow noreferrer"><code>setImmediate</code></a>, and <a href="http://nodejs.org/api/all.html#all_process_nexttick_callback" rel="nofollow noreferrer"><code>process.nextTick</code></a>. For your use case, <code>setImmediate</code> is probably the best choice, but <a href="https://stackoverflow.com/q/15349733/157247">see this question and its answers for more on that</a>. <code>setImmediate</code> looks like this:</p> <pre><code>setImmediate(functionToCall); </code></pre> <p>(It's a global, you don't have to <code>require</code> anything.)</p> <p>That does exactly what your title asks for: An asynchronous call to a synchronous function.</p> <hr> <p>From your comment below:</p> <blockquote> <p>I just need to create an async function inside which I call a normal synchronous function. When I mean asynchronous function I mean that when I call this function it doesn't obstruct the flow and the flow goes to the next function and this function can do something(like logging) after completion</p> </blockquote> <p>That's not quite the same thing your question asks. :-)</p> <p>First off, there are no asynchronous functions (in JavaScript). When you call a function in JavaScript, that function is executed synchronously. So that means you have two choices:</p> <ol> <li><p>The calling code can use <code>setImmediate</code> to tell Node to call the function asynchronously, or</p></li> <li><p>The function can do that for itself, probably using a nested function.</p></li> </ol> <p>Here's #1:</p> <pre><code>function foo() { console.log("A"); setImmediate(bar); console.log("B"); } function bar() { console.log("C"); } foo(); </code></pre> <p>which outputs:</p> <pre>A B C</pre> <p>Here's #2:</p> <pre><code>function foo() { console.log("A"); bar("C"); console.log("B"); } function bar(arg) { setImmediate(run); function run() { console.log(arg); } } foo(); </code></pre> <p>...which also outputs</p> <pre>A B C</pre> <p>Note how "C" was passed as an argument to <code>bar</code>. <code>bar</code> does nothing but schedule the callback to its nested function <code>run</code>. <code>run</code> uses the argument.</p>

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