Re: What is this inside a function?

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From	Thomas 'PointedEars' Lahn <PointedEars@web.de>
Newsgroups	comp.lang.javascript
Subject	Re: What is this inside a function?
Date	Mon, 08 Jun 2015 01:08:31 +0200
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Christoph M. Becker wrote:

> […] If […] the return statement's expression evaluates to an object, this
> very object is returned. E.g.
> 
>   function foo() {return {bar: "baz"}}
>   new foo // => {bar: "baz"}

Should be “function Foo” and “new Foo”, respectively.  JSHint is able to 
point that out with {newcap: true}, but the check will be moved to the 
JavaScript Code Style checker (JSCS) with the next major JSHint release:

<http://jshint.com/docs/options/#newcap> p.

> Cf. <http://ecma-international.org/ecma-262/5.1/#sec-13.2.2>.

Correct, and this has practical implications:

  function Person2(name, age)
  {
    if (!(this instanceof Person2)) return new Person2(name, age);

    this.name = name;
    this.age = age;
  }

and with JSX:

  function Person2(name, age)
  {
    if (!(this instanceof Person2)) return Person2.construct(arguments);

    this.name = name;
    this.age = age;
  }

See also Function.prototype.construct() and Function.prototype.construct2() 
in <http://PointedEars.de/wsvn/JSX/trunk/object.js>.

-- 
PointedEars
FAQ: <http://PointedEars.de/faq> | SVN: <http://PointedEars.de/wsvn/>
Twitter: @PointedEars2 | ES Matrix: <http://PointedEars.de/es-matrix>
Please do not cc me. / Bitte keine Kopien per E-Mail.

Thread

What is this inside a function? Steven D'Aprano <steve@pearwood.info> - 2015-06-08 00:21 +1000
  Re: What is this inside a function? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-06-07 19:58 +0100
    Re: What is this inside a function? "Christoph M. Becker" <cmbecker69@arcor.de> - 2015-06-07 21:19 +0200
      Re: What is this inside a function? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-06-07 20:43 +0100
      Re: What is this inside a function? Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-06-08 01:08 +0200
        Re: What is this inside a function? Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-06-12 19:19 +0200
    Re: What is this inside a function? Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-06-07 23:48 +0200

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