Making the Most of the JavaScript Language (2016)
thenorthcode.net
thenorthcode.net
The "use a more functional approach" and "take advantage of ES6" are by far the biggest for me. ES6 added so much good stuff, I wouldn't consider it optional. It's better than incremental upgrades, feels almost like a different language to me.
Every language has its quirks, and while I'll keep on hating Javascript's, I'll never lose sight of the fact that if you're holding out for the perfect language, you're not going to be doing much coding.
The only transpiler I've seen that gets close in terms of quality of output is BuckleScript, that thing is damn near magic but TS has the momentum and adoption.
TypeScript has been so good and caused me so few problems that I actually look at ways of moving more bits to the frontend, it makes it pleasant to work and I think (personally) the highest praise you can give a language is that it's pleasant.
Without it you frequently run into objects passed to you after going through 10k lines of code and it becomes a wicked game to figure out which properties the object actually has at that point.
JavaScript, even ES6, is IMO crap for large codebases.
Does this object have the property I'm looking for? Did somebody overwrite it with the wrong type 5000 lines ago? Why is the prototype chain broken? Where's my damn inline documentation.
My company has abandoned JavaScript wholesale with great relief. If it was a physical object we would have tossed it off the balcony.
> My company has abandoned JavaScript wholesale with great relief. If it was a physical object we would have tossed it off the balcony.
I would like to do the same with our gigantic SPA-ghetti.
(Though I'm still fan of the "rip off the Band-Aid" approach I used in a few projects back in the day: rename every .js to .ts and then fix compiler errors until things compile. allowJS is a great option now.)
I also believe dynamic language tooling has regressed.
I'd truthfully love to hear more about that. Care to elaborate?
Writing [1,2,3].map(function(x) { return x+10 }) really doesn't bother me. I don't see what the benefit is of an arrow function. Are there other things that you like?
As the OP mentions, the inheritance stuff is just likely to cause architecture headaches. I like JavaScript's concurrency model (single threaded with callbacks) so I don't see any benefit to the async stuff.
It just seems like people added a ton of complexity to give up a few keystrokes. Transpiling and shimming and adding more control structures make your application more complicated, so there is a real cost. And keystrokes are not generally a big problem when I'm programming. I'm not in a race.
const add = x => y => x +y;
...
[1,2,3,4].map(add(1));
Same goes for 'arguments', though that comes up less. Basically, they're much more representative of a simple lambda than a classical function.
From my experience at least, binding to the outer/creating scope is something I do very often, and as far as I know my use of JS is pretty idiomatic.
Concerning 1, being able to use terser, clearer syntax for something I do so often is a huge win, and in regards to 2, it's nice to see an arrow function and to immediately know what this means, and hella better than having to search for a .bind(), var self = this, var that = this, Car.method(), etc, all equally valid as an approach, and depending entirely on the whims of the programmer behind this code.
And honestly, the sugar often speaks to readability as well. Compare myArray.every(function (x) { return x; }); with myArray.every(x => x).
I don't understand your scope preference. These seem the same to me:
family.findEldestFirst(person => this.isRoyal() && person.name == "Kate")
family.findEldestFirst(isPrincess.bind(family))
function isPrincess(person) {
return this.isRoyal() && person.name == "Kate"
}
... And frankly I think using "this" that way in either case is not a win. I'd rather make family its own argument to isPrincess:
family.findEldestFirst(isPrincess.bind(null, family))
function isPrincess(family, person) {
return family.isRoyal() && person.name == "Kate"
}
Franky, my sense is that the people who like ES6 and promises are people who are just allergic to writing named functions. Named functions make callback hell go away, and they solve all the problems these arrow functions do. Somehow people think it's bad form to define lots of functions. But defining functions is my job. :) It doesn't bother me.
My sense is it's just Rubyists who miss Ruby and think "more Rubyish" is better. I sympathize because my path was BASIC -> PHP -> C# -> Ruby -> JavaScript. But I think it is a mistake to try to bring your old idioms to a new language.
... and if I wanted to reduce character count above all else, I'd just go use PERL.
I won't disagree about the added complexity.
It's either "only syntactic sugar" or it "added a ton of complexity". To be honest, you sound like someone who's bitter because all the hard stuff you had to learn to deal with is now super simple and intuitive.
> I like JavaScript's concurrency model (single threaded with callbacks) so I don't see any benefit to the async stuff.
This sentence also demonstrates you either don't understand the concurrency model or async/await (async/await doesn't change the concurrency model).
The syntactic sugar isn't only there to save keystrokes, it also makes code easier to read and is less prone to errors.
They made a real focus on tooling and it's been widely adopted.
In intellij it's as simple as turning on the option and creating a .ts file, the identically named js file is then dropped in the same directory (by default) and you just include that.
It's about 2 minutes from start to finish to setup.
Then it's a natural progression to using https://www.typescriptlang.org/docs/handbook/tsconfig-json.h...
I mean sure if you are going with a split bundle, hot code reloading and tree shaking via webpack then there is a high start cost but ts on it's own is rather fantastic.
vscode does the same thing as intellij if you want to try it without downloading intellij.
Excellent point, and one of the less-advertised benefits of using TypeScript.
I tend to use Babel/Webpack in most of my projects, mostly because I have the time to waste on keeping up with the 'bleeding edge' and I kind of enjoy it (in perhaps a slightly masochistic way).
That said, more than once I picked TypeScript for some project not primarily because of its main purpose, but rather because it offered a simple way to transpile 'ESNext' to ES5. Despite the fact that a basic Babel/Webpack setup is second nature to me now, it still feels easier to just use TypeScript to do all of it at once, and get types as part of the deal!
Its all a win.
Thus in your browser you see the code you write, you put in breakpoints as desired, and everything generally works.
I don't have much depth as to how it all works behind the scenes though, I'd love to know more.
That said, it is another thing you need to maintaining and depending on the number of transformations your code has to go through, you introduce more points where the source map can break.
Personally I'm a huge functional programming weenie for no reason I can coherently defend, so I prefer to avoid ES6 classes. But quite often they end up being the most reasonable solution to my problem, and having syntax for it is great. I just avoid them by default.
val or con would have been better.
I know some/most people don't care. I can't be one of them.
Maybe we'll get `val` in ES9.
/whistle .../
That said, I've come to terms with const, even if I find I accidentally use let sometimes from time spent in Lisp and F#.
Why wouldn't you always go for the most immuatable declaration? Even in C++, where you can have 'const int f(const int y) const;' it's still worth using even though you have to type it a few times.
Very true on both counts, but unfortunately the article perpetuates some of this misunderstanding.
> Where it gets interesting is when you return a function from an outer function...
Abbreviated example from the article:
var outer = function () {
var a = 1;
return function inner() {
return a;
};
};
I deal with this frequently on Stack Overflow. Someone asks a question where a closure is a great solution, and then someone answers with a complicated example involving a function that returns a function.
It seems to come up a lot in Google Maps API code:
var places = [
{ name:"Test", lat:10, lng:10 },
...
];
function initMap()
var map = new google.maps.Map(...);
for( var i = 0; i < places.length; ++i ) {
var marker = new google.maps.Marker(...);
// This is the complicated part:
marker.addListener( 'click', (function( marker ) {
return function() {
// This works because of the closure:
infowindow.open( map, marker );
}
})( marker ) );
}
}
function initMap()
var map = new google.maps.Map(...);
for( var i = 0; i < places.length; ++i ) {
addMarker( places[i] );
}
function addMarker( place ) {
var marker = new google.maps.Marker(...);
marker.addListener( 'click', function() {
// We have a closure here too:
infowindow.open( map, marker );
});
}
}
Of course, the same thing can be done with forEach():
function initMap()
var map = new google.maps.Map(...);
places.forEach( addMarker );
function addMarker( place ) {
var marker = new google.maps.Marker(...);
marker.addListener( 'click', function() {
// We have a closure here too:
infowindow.open( map, marker );
});
}
}
function initMap()
var map = new google.maps.Map(...);
places.forEach( function( place ) {
var marker = new google.maps.Marker(...);
marker.addListener( 'click', function() {
// We have a closure here too:
infowindow.open( map, marker );
});
});
}