I read Douglas Crockford's JavaScript: The Good Parts over the long weekend. My interests were partially pedagogical. A huge part of my current job involves mentoring more junior developers and helping them to learn. One of my interests was whether Crockford's book would be a good resource to pass along. It seems like a silly question. The book is still the book best known for putting JavaScript on the map as a quasi-respectable language. I learned JavaScript the way I have learned most languages which is to say, in the school of hard knocks. I had learned most of the good and bad parts of JavaScript through trial, error, Google and JSLint. The book wasn't a bad refresher, but there weren't a lot of new insights, either.

The timing makes the question genuinely difficult. ECMAScript 6 is out and some of the features are available now, more are available through polyfill and most of the rest could be acquired through Babel (https://babeljs.io/).

The book is, in a sense, almost obsolete. Almost. A good example of what I mean is prototypical inheritance. Crockford spends a lot of time explaining how class-based inheritance is different than prototypical inheritance. This is still relevant. JavaScript has remained a prototypical language. He also shows several techniques to make the meaning of JavaScript programs more clear to those used to classical object-oriented programming. This part is less relevant. Today, I would reach for the ES6 class syntactic sugar (via Babel for the browser) or CoffeeScript rather than layering some manual code over the prototype.

Similarly, Crockford discusses variable scoping at length. Again, this is partially relevant. The base scopes haven't changed and they still easily trip up many programmers (I have used questions about JavaScript scopes to trip people up on interviews). These things need to be understood. However, the let statement in ES6 does provide some clearer semantics and its use should be encouraged as ES6 becomes widely available.

There are also new parts which, good or bad, require some level of explanation. Generators and promises will require explanation and, of course, categorization as either good or bad parts.

This sort of thing leaves me in a place where I want to recommend Crockford, but I feel the need to add some general commentary. Hopefully, a second edition of JavaScript: The Good Parts will come out in the next few years and make these little oddities of time go away.