Javascript collection

Question

sorry for noobie question. Can you explain please, what is the difference between:

1. var a = [];
   a[\'b\'] = 1;

2. var a = {};
   a[\'b\'] = 1;
         


        

Answer 1

1) Is an Array 2) Is an Object

With Array all is usual as in other languages

With Object also. - You can get value a.b == 1 - But in JS you can also get value with such syntax a["b"] == 1

• This could be usefull when key look like something this "some key", in this case you can't use "chaining"
• also this usefull if key is the variable

you can write like this

    function some(f){
var Object = {name: "Boo", age: "foo"}, key;
if(f == true){
   key = "name";
}else{
   key = "age";
}
 return Object[key];
}

but I want to use it as collection, which I have to choose?

This depends of what data you want to store