Can I get a javascript object property name that starts with a number?

Question

var myObj = {"suppliers":[{"name":"supplier1","12m":"0.08","24m":"0.06"}]};

alert(myObj.suppliers[0].12m);

Is there a different way to get this property, or should I just not use a key that starts with a number?

Answer 1

You can use the following syntax to do what you describe using bracket notation :

myObject["myProperty"]

Bracket notation differs from dot notation (eg myObject.myProperty ) in that it can be used to access properties whose names are illegal. Illegal meaning that with dot notation, you're limited to using property names that are alphanumeric (plus the underscore _ and dollar sign $ ), and don't begin with a number. Bracket notation allows us to use a string to access a property and bypass this.

myObject.1 // fails, properties cannot begin with numbers
myObject.& // fails, properties must be alphanumeric (or $ or _)

myObject["1"] // succeeds
myObject["&"] // succeeds

This also means we can use string variables to look up and set properties on objects:

var myEdgyPropertyName = "||~~(_o__o_)~~||";

myEdgyObject[myEdgyPropertyName] = "who's there?";

myEdgyObject[myEdgyPropertyName] // "who's there?";

You can read more about dot and bracket notation here, on MDN .

Answer 2

Yes, use bracket syntax:

alert(myObj.suppliers[0]["12m"]);

From MDN

A JavaScript identifier must start with a letter, underscore (_), or dollar sign ($); subsequent characters can also be digits (0-9). Because JavaScript is case sensitive, letters include the characters "A" through "Z" (uppercase) and the characters "a" through "z" (lowercase).