Scripter Javascript Tutorial

50 Get data from an object

There are multiple ways to get properties of an object.

var scale = {
		"name" : "C Major",
		"pitches" : [60, 62, 64, 65, 67, 69, 71]
	};
	
var name = scale.name;
var pitches = scale["pitches"];
var name2 = scale[0];

In the above example:

• Lines 1–4 declare a simple object.

• Line 6 is dot notation, literally the name of the property appended to the object’s name with a dot or period. Dot notation can be used as long as the key follows the rules for variable names.

• Line 7 is the same as an array with square bracket notation. Keys consisting of multiple words in a string can be used here.

• Line 8 treats the object just like an array and uses the index for the first key to get the value.

If a key is used which is not actually in the object, then the object will return undefined.