The third slide of Ryan Dahl's 2009 JSConf.eu presentation (https://www.youtube.com/watch?v=ztspvPYybIY https://www.youtube.com/watch?v=ztspvPYybIY) covers most

The third slide of Ryan Dahl's 2009 JSConf.eu presentation (https://www.youtube.com/watch?v=ztspvPYybIY https://www.youtube.com/watch?v=ztspvPYybIY) covers most of the reasons for why it was made: "I/O needs to be done differently". Evented I/O via event loops wasn't really that much of a thing back then, and many server-side web frameworks were simply sitting idle whilst waiting on I/O. Node changed this, and thereby enabled a kind of concurrency that was easy to achieve and there by default, often without the programmer really realizing it, because they didn't have to do anything too special to get it done other than write JavaScript with callbacks. I don't think JavaScript was really the point of it. (EDIT: but JavaScript having functions as a first-class citizen, and closures, makes it a very good candidate for something that leverages event loops for this kind of thing)