FAQ Entry Proposal: What is (function(){ /*...*/ })() ?
in [JavaScript]
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From: Garrett Smith on 3 Mar 2010 02:14 Richard Cornford wrote: > On Feb 27, 7:59 am, Garrett Smith wrote: [...] >> I also propose the removal that the final paragraph of that section >> (below). The article already discusses [[Prototype]], but uses the >> term "prototype" to describe it. I prefer to use the spec's >> [[Prototype]] notation to avoid confusion between a Function's >> prototype property and Objects' internal [[Prototype]] property. > > Objects in ECMAScript have prototypes, and calling them an object's > prototype is completely appropriate. "[[Prototype]]" is the name of > the internal property of the object that refers to its prototype (or > the first object on its prototype chain). It might be acceptable for > people familiar with ECMAScript and its prototypes to use > "[[Prototype]]" as a shorthand for an object's prototype chain but > that usage is inappropriate in the closures document. > When refering to MyObject1's prototype, it is important to be disambiguate the "MyObject1.prototype" MyObject1's prototype (i.e. "Function.prototype"). > Use:- > > | The instance of MyObject2 referred to by the objectRef variable has > | a prototype chain. The first object in that chain is the instance > | of MyObject1 that was created and assigned to the prototype > | property of the MyObject2 constructor. The instance of MyObject1 > | has a prototype, the object originally assigned to the MyObject1 > | function's prototype property by default (and which has no > | properties of its own). That object has a prototype, the default > | Object prototype that corresponds with the object referred to by > | Object.prototype. Object.prototype has a null prototype so the > | prototype chain comes to an end at this point. > > The proposed diagram is inappropriate. > That is your opinion. My opinion is that a diagram (and not necessarily that one) would help break up the article and make it less verbose. The parenthetical regarding MyObject1 function's prototype property:- "(and which has no properties of its own)" - is wrong. Function MyObject1 was given a prototype property by the implementation (this happens with all user-defined functions). The value of that property is an object that has a `constructor` property that points to MyObject1. Why not remove that parenthetical and instead mention that MyObject1.prototype was /automatically/ created by the implementation? -- Garrett comp.lang.javascript FAQ: http://jibbering.com/faq/
From: Dr J R Stockton on 3 Mar 2010 18:30 In comp.lang.javascript message <hml29c$6pq$1(a)news.eternal- september.org>, Tue, 2 Mar 2010 23:14:45, Garrett Smith <dhtmlkitchen(a)gmail.com> posted: > >That is your opinion. My opinion is that a diagram (and not necessarily >that one) would help break up the article and make it less verbose. With a copy of <URL:http://www.merlyn.demon.co.uk/js-grphx.htm>, diagrams can be drawn in JavaScript and saved to PNG. <URL:http://www.merlyn.demon.co.uk/$lag-pts.htm> shows an animated diagram done in JavaScript. -- (c) John Stockton, nr London, UK. ?@merlyn.demon.co.uk Turnpike v6.05 MIME. Web <URL:http://www.merlyn.demon.co.uk/> - FAQqish topics, acronyms & links; Astro stuff via astron-1.htm, gravity0.htm ; quotings.htm, pascal.htm, etc. No Encoding. Quotes before replies. Snip well. Write clearly. Don't Mail News.
From: Garrett Smith on 5 Mar 2010 23:10 Garrett Smith wrote: > Richard Cornford wrote: >> On Feb 27, 7:59 am, Garrett Smith wrote: [...] > The parenthetical regarding MyObject1 function's prototype property:- > "(and which has no properties of its own)" - is wrong. Function > MyObject1 was given a prototype property by the implementation (this > happens with all user-defined functions). The value of that property is > an object that has a `constructor` property that points to MyObject1. > > Why not remove that parenthetical and instead mention that > MyObject1.prototype was /automatically/ created by the implementation? e.g. | The instance of MyObject2 referred to by the objectRef variable has | a prototype chain. The first object in that chain is the instance | of MyObject1 that was created and assigned to the prototype | property of the MyObject2 constructor. The instance of MyObject1 | has a prototype, the object that was assigned to the function | MyObject1's prototype property by the implementation. That object has | a prototype, the default Object prototype that corresponds with the | object referred to by Object.prototype. Object.prototype has a null | prototype so the prototype chain comes to an end at this point. ? -- Garrett comp.lang.javascript FAQ: http://jibbering.com/faq/
From: Garrett Smith on 10 Mar 2010 23:44
Garrett Smith wrote: > Garrett Smith wrote: >> Richard Cornford wrote: >>> On Feb 27, 7:59 am, Garrett Smith wrote: [...] > e.g. > | The instance of MyObject2 referred to by the objectRef variable has > | a prototype chain. The first object in that chain is the instance > | of MyObject1 that was created and assigned to the prototype > | property of the MyObject2 constructor. The instance of MyObject1 > | has a prototype, the object that was assigned to the function > | MyObject1's prototype property by the implementation. That object has > | a prototype, the default Object prototype that corresponds with the > | object referred to by Object.prototype. Object.prototype has a null > | prototype so the prototype chain comes to an end at this point. > > ? I've uploaded the article with that very text at: /faq/notes/closures/ -- Garrett comp.lang.javascript FAQ: http://jibbering.com/faq/ |