How does one read JavaScript API like Mongoose

Question

I'm a java developer. I really like to learn javascript. I'm finding it very difficult to pick-up a library and just learn/use it for two reasons: 1) There is no decent auto-complete. I've tried, eclipse, vjet, nodeclipse and webstorm...each has its own frustrating set of issues. Maybe the language is such that, autocomplete is super-difficult. 2) The API documentation is extremely confusing. I guess it is because I'm new to JavaScript.

For example, I wanted to figure what the callback function in mongoose.connect method does and how to declare it. So I checked the api doc. All it says is that the callback is a function...it doesn't say how many params it takes, what the values of the params are under various invocation scenarios...etc.

I feel like I'm missing something...

How does one go about reading these docs?

Answer 1

It's not you. I often find myself scratching my head about what the callback arguments should be. It's a problem with many JavaScript libraries.

However, in Node at least there is a convention that most libraries follow:

In node.js, it is considered standard practice to handle errors in asynchronous functions by returning them as the first argument to the current function's callback. If there is an error, the first parameter is passed an Error object with all the details. Otherwise, the first parameter is null.

For what it's worth, I haven't yet found an IDE that offers JavaScript autocomplete at anything nearly approaching the level of what's available for Java.

For the connect function, the callback passes an error argument given failure:

mongoose.connect('mongodb://localhost/dbname', function(err) {
    if (err) {
      // handle error
    }
});

Answer 2

Generally, JavaScript tools are behind those for Java.

I feel like I'm missing something...

Me too. But, I think situation will change in 1-2 ears.

You can just wait for things to change or improve that you need by small step in a time. Welcome to Nodeclipse.

It is time inefficient to solve problem only for one library (e.g. Mongoose), but if there is web service like one for Node.js there is big chance for things change. Especially if you care enough to contribute, e.g. with ideas and materials or just raising an issue.