Prototype

Most of the Javascript code are objects, but interestingly Javascript do not have class concept. Instead it will use prototype.

When we define a constructor function below like that, an object prototype is created. Anything defined in prototype can be accessed by all the instances.

var Object = function(a, b) {
  this.attributeA = a;
  this.attributeB = b;
}

When we define a method within prototype, it can be access by all the instances (they are objects as well, so confusing). And it’s static as well.

Object.prototype.methodA = function() {
  // Logic goes here.
}

More details please check this Codepend.

Callback function

callback is used very often in Javascript. callback decouple the host and callback function itself. We could use it in these senario:

• Provide a interface to be invoked by different objects.
• Pass value to callback function on the fly/dynamically.
• Event driven - execute only when the event triggered.

Here’s a Codepen about callback function.

Hoisting

Mis-understanding hoisting will cause some error difficult to detect.

And I think this concept is quite unique/ odd behaviours exist in Javascript ONLY.

This is a stackoverflow link have sample and detail explanation about hosting.

Recursive function

This is a recursive function experiment.