ES6: The features I'm most excited about

Post by tlrobinson » Mon, Jul 06, 2015, 9:41 AM UTC

amelius wrote: post #88

tlrobinson wrote: post #35

I agree with this list completely, but it doesn't mention one of the best reasons generators and promises are awesome: async/await-style asynchronous programming eliminates callback hell by letting you write asynchronous code as if it were synchronous, including using control structures like conditionals, loops, and try/catch. And you can do it in (most) browsers today using a transpiler like Babel and a library like…

The problem with Javascript generators, however, is that you're not allowed to call other functions from them, which yield. This very much limits the kind of async stuff you can do with them.

    async function funcA() {
      await sleep(1000);
      // ...

Post by jestar_jokin » Mon, Jul 06, 2015, 9:47 AM UTC

dmak wrote: post #90

spion wrote: post #76

I don't understand why everyone considers classes controversial. If you look at code in the wild, it already does what classes desugar to: everyone already writes constructor function and attaches properties to their prototypes. At least now with classes, users coming from other languages wont be as tempted to make their own completely incompatible object systems.

While my example isn't an issue in ES6, most of the controversial came from CoffeeScript. Using classes comes with classical inheritance expectations. In CoffeeScript, changing class variables would carry through all instances, and that is unexpected from a classical inheritance point of view. However, it made complete sense in the compiled JS.

Post by alkonaut » Mon, Jul 06, 2015, 10:31 AM UTC

dmak wrote: post #91

alkonaut wrote: post #89

Earlier quoted context omitted.

Can someone explain the reasoning behind having any kind of backwards compatibility? Who would pick a worse-but-compatible ES6 over a better incompatible version? For example, the scoping rules: why have two separate scoping rules for let and var? To put it another way, would ES6 have let and var with differing scoping rules if it was designed today? If not, then it's a flaw (any difference from what a clean redesign…

What about it is not simple and consistent? Two different syntaxes, and two different expectations and rules. Var is function scope, and let is block scope.

Post by neoeldex » Mon, Jul 06, 2015, 10:54 AM UTC

spion wrote: post #76

I don't understand why everyone considers classes controversial. If you look at code in the wild, it already does what classes desugar to: everyone already writes constructor function and attaches properties to their prototypes. At least now with classes, users coming from other languages wont be as tempted to make their own completely incompatible object systems.

Post by zoz » Mon, Jul 06, 2015, 11:45 AM UTC

  constructor(x = 0, y = 0) {
    this.x = x;
    this.y = y;
  }