When would you use hasOwnProperty on an array?

Question

I have just seen an example where the code is as follows:

var schemaSet:Array = currentScope();
if (schemaSet.hasOwnProperty("current"))
    schema = schemaSet["current"];

I have never seen this before. I checked the as3 docs and didn't find any information on it. Note: This code is from SchemaManager.currentSchema() written by an Adobe employee.

When and where would you use this? Is this better than or equivalent to:

if (schemaSet.indexOf("current")!=-1)

Answer 1

There are two types of data:

• Normal arrays, which contain only values and the keys are numeric, starting from 0.

• And there are also objects, where every element has a string (it can also be a number too) key.

If you want to check if an array contains a value, you will go with .indexOf() method.

var myArray = ["a", "b", "c"];

if (myArray.indexOf("a") > -1) return true;

If you want to check if an object has an element with a certain key, then you will go for hasOwnProperty() method.

var myObject = {a: "letter a", b: "letter b"}

if (myObject.hasOwnProperty("a")) return true;