Javascript's variables grouping with object acting like namespace

Posted on: 2011-11-17

In Javascript, if you need to have multiple global variable in a script you could finish with something like a chunk of var.

var v1; 
var v2; 
var v3; 
var v4; 
var v5; 

This can cause problem because, maybe someone will need to define a variable with the same name (locally or globally). To reduce this problematic, you can use Javascript object notation (JSON). By using JSON syntax you can create a "virtual" namespace with an object. I say "virtual namespace" because it's not a namespace. In fact, it's an object... but it's created just to group variable instead if letting them wild at the top of a Javascript file. This is pretty important because if a web page include many Javascript file this could end having 2 files using the same variable name which would override the value of the other.

var mynamespace = { 
  "v1":"value1" ,
  "v2":"value2" ,
  "v3":"value3" ,
  "v4":"value4" ,
  "v5":"value5" ,
  "v6":"value6" 
}; 

This way, instead of using in your code v1 directly you use the object v1.

mynamespace.v1 = "Patrick";

//...

if(mynamespace.v1 == "Unknown") { 
  //... 
} 

This post cover only the basic. You can have multiple level of deepest as JSON let you have inner array or "object". I'll cover this later.