Create library like jQuery style

Question

var jQuery = function( selector ) {
    return new jQuery.fn.init( selector );
};

jQuery.fn = jQuery.prototype = {...};

var init = jQuery.fn.init = function( selector ){
    this.selector   = selector;
    this.element    = document.querySelector(this.selector);
};

console.log(
    jQuery('div').selector
);

I'm currently study how jQuery works, but I got few questions

jQuery.fn = jQuery.prototype = {}; why prototype = object, isn't prototype usually come with name after jQuery.prototype.foo = function...
var init = jQuery.fn.init (jQuery.prototoype.init) when I remove var init, i got an error, like this : var jQuery.fn.init = ...

Nitesh · Accepted Answer · 2016-12-25 15:16:16Z

1

1) jQuery.fn = jQuery.prototype = {}; why prototype = object

Actually, prototype is an object only when you do something like,

**jQuery.prototype.get = function(){
 //Code
}**

You are actually creating a member function in prototype object only with name "get". You could have done it like this also as:

**jQuery.prototype = {
  "get" : function(){
  }
}**

2) When you remove init, the statement becomes as var jQuery.fn.init = ...

Actually this is not a valid statement because jQuery object is already available. It is a syntactical error. You cannot create a member of any object like this. For that, you just need to do as

**jQuery.fn.init = function(){
}**

answered Dec 25, 2016 at 15:16

Nitesh

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1 Comment

Benjamin W Over a year ago

is jQuery.fn.init = jQuery.prototype.init? is this relate to jQuery.prototype ={} object?

NikxDa · Accepted Answer · 2016-12-25 15:19:02Z

1

Setting the prototype to be an empty object clears every left-over from the JavaScript side and makes it a completely new "class" or object.
When you remove the var-part, you basically remove the complete definition. A variable name cannot contain dots, because a dot by definition requires an object. Therefore, var a.b.c = 1 will not be valid. You need to have an object a = { b: {} } and then do a.b.c = 1.

answered Dec 25, 2016 at 15:19

NikxDa

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