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You're using a callback to return a value which doesn't make a lot of sense because your Project.findById() returns immediately, without waiting for the provided callback to complete. Don't feel bad though, the programming model that nodejs uses is somewhat difficult at first to wrap your head around. In event-driven programming (EDP), we provide callbacks to accomplish results, ignoring their return values since we never know when the callback might actually be called. Here's a quick example. Suppose we want to write the result of an HTTP request into a file. In a procedural (non-EDP) programming environment, we rely on functions that only return values when they have them to return. So we might write something like (pseudo-code): <pre><code> url = 'http://www.example.com' filepath = './example.txt' content = getContentFromURL(url) writeToFile(filepath,content) print "Done!" </code></pre> which assumes that our program will wait until getContentFromURL() has contacted the remote server, made its request, waited for a result and returned that result to the program. The writeToFile() function then asks the operating system to open a local file at some filepath for write, waiting until it is told the open file operation has completed (typically waiting for the disk driver to report that it can carry out such an operation.) writeToFile() then requests that the operating system write the content to the newly opened file, waiting until it is told that the driver the operating system uses to write files tells it it has accomplished this goal, returning the result to the program so it can tell us that the program has completed. The problem that nodejs was created to solve is to better use all the time wasted by all the waiting that occurs above. It does this by using functions (callbacks) which are called when operations like retrieving a result from a remote web request or writing a file to the filesystem complete. To accomplish the same task above in an event-driven programming environment, we need to write the same program as: <pre><code> getContentFromURL(url,onGetContentFromURLComplete) function onGetContentFromURLComplete(content,err){ writeToFile(content,onWriteToFileComplete); } function onWriteToFileComplete(err){ print "Done!"; } </code></pre> where <ul> <li>calling getContentFromURL() only calls the onGetContentFromURLComplete callback once it has the result of the web request and </li> <li>calling writeToFile() only calls its callback to display a success message when it completes writing the content successfully.</li> </ul> The real magic of nodejs is that it can do all sorts of other things during the surprisingly large amount of time procedural functions have to wait for most time-intensive operations (like those concerned with input and output) to complete. (The examples above ignore all errors which is usually considered a bad thing.)
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1. PONode.js server GET to separate API failing after a few hours of use
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1. USRob Raisch
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1. USRob Raisch
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1. COI downvoted your answer. While I agree that beck's style with returning in every statement is unusual, the code seems alright -- and if you were right, I don't know how it would work 100 times and then stop working?
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 USLinus Gustav Larsson Thiel
2. COThank you for the full answer Rob, very informative. The return value at the end is because it is written in coffeescript and I copy and pasted the compiled code over as js is more widely know. The return is irrelevant in that situation as nothing is using it.
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