ActionScript: The Definitive Guide

Name

Object.toString( ) Method — the value of the object, as a string

Availability

Flash 5

Synopsis

someObject.toString( )

Returns

An internally defined string that describes or otherwise represents the object.

Description

The toString( ) method returns a string description for someObject. By default, someObject .toString( ) returns the expression:

"[object " + class + "]"

where class is the internally defined name of the class to which someObject belongs. The ActionScript interpreter automatically invokes the toString( ) method whenever someObject is used in a string context. For example:

x = new Object( );
trace(x);       // Displays: "[object Object]"

Most classes overwrite the default toString( ) method of Object in order to provide more meaningful information about each member of the class. For example, the Date.toString( ) method returns the date and time, and the Array.toString( ) method returns a comma-separated list of array elements. We may do the same when constructing our own classes.

Example

This example shows how to provide a custom toString( ) method for the Ball class that we created in Chapter 12:

// Add a Custom toString() method // Make the Ball constructor function Ball (radius, color, xPosition, yPosition) { this.radius = radius; this.color = color; this.xPosition = xPosition; this.yPosition = yPosition; } // Assign a function literal to the Ball class prototype's toString() method Ball.prototype.toString = function ( ) { return "A ball with the radius " + this.radius; }; // Create ...