ExtendScript reflection interface¶
ExtendScript provides a reflection interface that allows you to find out everything about an object, including its name, a description, the expected data type for properties, the arguments and return value for methods, and any default values or limitations to the input values.
Reflection object¶
Every object has a reflect property that returns a reflection object that reports the contents of the object. You can, for example, show the values of all the properties of an object with code like this:
var f = new File ("myfile");
var props = f.reflect.properties;
for (var i = 0; i < props.length; i++) {
$.writeln('this property ' + props[i].name + ' is ' + f[props[i].name]);
}
Reflection object properties¶
All properties are read only.
description |
String |
Short text describing the reflected object, or undefined if no description is available. |
help |
String |
Longer text describing the reflected object more completely, or
|
methods |
Array of ReflectionInfo |
An Array of ReflectionInfo object containing all methods of the reflected object, defined in the class or in the specific instance. |
name |
String |
The class name of the reflected object. |
properties |
Array of ReflectionInfo |
An Array of ReflectionInfo object containing all properties of the reflected object, defined in the class or in the specific instance. For objects with dynamic properties (defined at runtime) the list contains only those dynamic properties that have already been accessed by the script. For example, in an object wrapping an HTML tag, the names of the HTML attributes are determined at run time. |
Reflection object functions¶
find()¶
reflectionObj.find (name)
name |
The property for which to retrieve information. |
Returns the ReflectionInfo object for the named property of the reflected object, or null if no such property exists.
Use this method to get information about dynamic properties that have not yet been accessed, but that are known to exist.
Examples¶
This code determines the class name of an object:
obj = new String ("hi");
obj.reflect.name; // => String
This code gets a list of all methods:
obj = new String ("hi");
obj.reflect.methods; //=> indexOf,slice,...
obj.reflect.find ("indexOf"); // => the method info
This code gets a list of properties:
Math.reflect.properties; //=> PI,LOG10,...
This code gets the data type of a property:
Math.reflect.find ("PI").type; // => number
ReflectionInfo object¶
This object contains information about a property, a method, or a method argument. You can access ReflectionInfo objects in a Reflection object’s properties and methods arrays, by name or index:
obj = new String ("hi");
obj.reflect.methods[0];
obj.reflect.methods["indexOf"];
You can access the ReflectionInfo objects for the arguments of a method in the arguments array of the ReflectionInfo object for the method, by index:
obj.reflect.methods["indexOf"].arguments[0];
obj.reflect.methods.indexOf.arguments[0];
ReflectionInfo object properties¶
arguments |
Array of ReflectionInfo |
For a reflected method, an array of ReflectionInfo objects describing each method argument. |
dataType |
String |
The data type of the reflected element. One of:
|
defaultValue |
any |
The default value for a reflected property or method argument, or
|
description |
String |
Short text describing the reflected object, or |
help |
String |
Longer text describing the reflected object more completely, or
|
isCollection |
Boolean |
When |
max |
Number |
The maximum numeric value for the reflected element, or
|
min |
Number |
The minimum numeric value for the reflected element, or |
name |
String Number |
The name of the reflected element. A string, or a number for an array index. |
type |
String |
The type of the reflected element. One of:
|