UX Design and Development course

Properties

Object's property is a propertyName: propertyValue pair, where property name can be only a string. If it's not a string, it gets casted into a string. You can specify properties when creating an object or later. There may be zero or more properties separated by commas.

var language = {
    name: 'JavaScript',
    isSupportedByBrowsers: true,
    createdIn: 1995,
    author:{
        firstName: 'Brendan',
        lastName: 'Eich'
    },
 // Yes, objects can be nested!
    getAuthorFullName: function(){
        return this.author.firstName + this.author.lastName;    
    }
 // Yes, functions can be values too!
};

The following code demonstates how to get a property's value.

var variable = language.name;
 // variable now contains "JavaScript" string.
    variable = language['name'];
 /* The lines above do the same thing. The difference is that the second one lets you use litteraly any string as a property name, but it's less readable. */
    variable = language.newProperty; 
 // variable is now undefined, because we have not assigned this property yet.

The following example shows how to add a new property or change an existing one.

language.newProperty = 'new value';
 // Now the object has a new property. If the property already exists, its value will be replaced.
language['newProperty'] = 'changed value';
 // Once again, you can access properties both ways. The first one (dot notation) is recomended.