Re: custom event in IE

From	Scott Sauyet <scott@sauyet.com>
Newsgroups	comp.lang.javascript
Subject	Re: custom event in IE
Date	2017-01-14 23:01 +0000
Organization	A noiseless patient Spider
Message-ID	<o5eal0$4ib$1@dont-email.me> (permalink)
References	(1 earlier) <8bydnVoLx8BUq-nFnZ2dnUU7-bednZ2d@westnet.com.au> <4259298.GXAFRqVoOG@PointedEars.de> <drGdnYqmpYpK_unFnZ2dnUU7-bfNnZ2d@westnet.com.au> <20170110215212.00003a50@gmail.com> <1747068.usQuhbGJ8B@PointedEars.de>

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Thomas 'PointedEars' Lahn wrote:

> You cannot determine whether a function can be called as a constructor
> unless you try it.

What would count as positive evidence that a function can actually be 
called *reasonably* as a constructor function?

Clearly, we can find evidence that it cannot be.  Many function will 
throw TypeErrors if one attempts to call them as constructor functions.  
But the fact that a particular function doesn't do so is clearly not 
sufficient to show that it can reasonably be used as a constructor 
function.  For example:

    var fn = (function() {
      var g = {}; 
      return function() {return g;};
    }());

    // no errors here
    var obj1 = new fn();
    var obj2 = new fn();

    obj1.foo = 'bar'
    obj2; //=> {foo: 'bar'}

`fn` cannot reasonably be used as a constructor function.

So are there any clear criteria to make clear that a function *can* be 
used as a constructor?

  -- Scott

Thread

custom event in IE Andrew Poulos <ap_prog@hotmail.com> - 2017-01-10 12:08 +1100
  Re: custom event in IE Andrew Poulos <ap_prog@hotmail.com> - 2017-01-10 12:20 +1100
    Re: custom event in IE Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2017-01-10 02:45 +0100
      Re: custom event in IE Andrew Poulos <ap_prog@hotmail.com> - 2017-01-10 15:32 +1100
        Re: custom event in IE Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2017-01-10 12:53 +0100
          Re: custom event in IE Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2017-01-11 08:25 +0100
        Re: custom event in IE James Kirk <noneya.invalid@gmail.com> - 2017-01-10 21:52 -0500
          Re: custom event in IE Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2017-01-11 04:09 +0100
            Re: custom event in IE James Kirk <noneya.invalid@gmail.com> - 2017-01-11 21:31 -0500
              Re: custom event in IE Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2017-01-12 14:22 +0100
            Re: custom event in IE Scott Sauyet <scott@sauyet.com> - 2017-01-14 23:01 +0000
              Re: custom event in IE "Michael Haufe (TNO)" <tno@thenewobjective.com> - 2017-01-15 09:51 -0800
                Re: custom event in IE Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2017-01-15 22:37 +0100
                Can we recognize Constructor Functions (was: custom event in IE) Scott Sauyet <scott@sauyet.com> - 2017-01-15 23:39 +0000
                Re: custom event in IE Scott Sauyet <scott@sauyet.com> - 2017-01-15 23:15 +0000
                Re: custom event in IE "Michael Haufe (TNO)" <tno@thenewobjective.com> - 2017-01-15 22:36 -0800
                Re: custom event in IE Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2017-01-16 12:54 +0100
                Re: custom event in IE "Michael Haufe (TNO)" <tno@thenewobjective.com> - 2017-01-16 14:18 -0800
                Re: custom event in IE Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2017-01-17 00:24 +0100

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