ActionScript: The Definitive Guide

Name

Boolean( ) Global Function — convert a value to the boolean datatype

Availability

Flash 5

Synopsis

Boolean(value)

Arguments

value

An expression containing the value to be converted to a Boolean.

Returns

The result of converting value to a primitive Boolean (either true or false).

Description

The Boolean( ) global function converts its argument to a primitive Boolean value and returns that converted value. The results of converting various types of data to a primitive Boolean are described in Table 3.3. It’s normally not necessary to use the Boolean( ) function; ActionScript automatically converts values to the boolean type when appropriate.

Usage

Be sure not to confuse the global Boolean( ) function with the Boolean class constructor. The Boolean( ) function converts its argument to the boolean datatype, whereas the Boolean class constructor creates a new Boolean object. Note that in ECMA-262, all nonempty strings convert to true. In Flash 5, only strings that can be converted to a valid nonzero number convert to true. Therefore, even the string “true” converts to the Boolean false.

Example

var x = 1;
if (Boolean(x)) {
  trace("x is true");
}

See Also

The Boolean class; Section 3.4 in Chapter 3