A re-introduction to JavaScript

Post by hikz » Sat, May 09, 2015, 10:12 AM UTC

Post by efbbbf » Sat, May 09, 2015, 1:31 PM UTC

Post by sergiotapia » Sat, May 09, 2015, 1:40 PM UTC

serve_yay wrote: post #4

Very nice to see it starts off with a (correct) discussion of JS types! JS devs mostly don't know the actual types in JS, which is pretty crazy if you think about it.

Post by Roodgorf » Sat, May 09, 2015, 2:19 PM UTC

efbbbf wrote: post #3

https://news.ycombinator.com/item?id=7169513 https://news.ycombinator.com/item?id=3569893 https://news.ycombinator.com/item?id=1524450 https://news.ycombinator.com/item?id=601967

Post by csandreasen » Sat, May 09, 2015, 2:48 PM UTC

sergiotapia wrote: post #5

serve_yay wrote: post #4

Very nice to see it starts off with a (correct) discussion of JS types! JS devs mostly don't know the actual types in JS, which is pretty crazy if you think about it.

I think 99% of the problems people have with Javascript are not actually types, but `this`. It's the most confusing part about Javascript. This context, var foo scope, what? Why is this value not updating? undefined? What???

  >>> class foo():
  ...   def test(this, x):
  ...     print this, x
  ... 
  >>> x = foo()
  >>> x
  
  >>> x.test(1)
   1
  >>> y = foo.test
  >>> y(1)
  Traceback (most recent call last):
    File "", line 1, in 
  TypeError: unbound method test() must be called with foo instance as first argument (got int instance instead)
  >>> y(x,1)
   1

  function foo() { }
  foo.prototype.test = function(x) {
    console.log(this, x);
  }
  var x = new foo();
  x.test(1); // prints VM1061:4 foo {test: function} 1
  var y = x.test;
  y(1); // prints VM1061:4 Window {top: Window, window: Window, …} 1