JavaScript-1.5 Reference

JS_DefinePropertyWithTinyId

Function

Summary

Creates a single property for a specified object and assigns it an ID number.

Syntax

JSBool JS_DefinePropertyWithTinyId( JSContext *cx,
    JSObject *obj, const char *name, int8 tinyid, jsval value,
    JSPropertyOp getter, JSPropertyOp setter, uintN flags);

Name	Type	Description
`cx`	`JSContext *`	Pointer to a JS context from which to derive runtime information.
`obj`	`JSObject *`	Object for which to create the new property.
`name`	`const char *`	Name for the property to create.
`tinyid`	`int8`	8-bit ID to aid in sharing `getProperty`/`setProperty` methods among properties.
`value`	`jsval`	Initial value to assign to the property.
`getter`	`JSPropertyOp`	`getProperty` method for retrieving the current property value.
`setter`	`JSPropertyOp`	`setProperty` method for specifying a new property value.
`flags`	`uintN`	Property flags.

Description

JS_DefinePropertyWithTinyId defines a single property for a specified object, obj.

name is the name to assign to the property in the object. value is a jsval that defines the property's data type and initial value.

tinyid is an 8-bit value that simplifies determining which property to access, and is especially useful in getProperty and setProperty methods that are shared by a number of different properties.

getter and setter identify the getProperty and setProperty methods for the property, respectively. If you pass null values for these entries, JS_DefinePropertyWithTinyId assigns the default getProperty and setProperty methods to this property. flags contains the property flags to set for the newly created property. The following table lists possible values you can pass in flags, either singly, or OR'd together:

Flag Purpose

JSPROP_ENUMERATE
Property is visible in for and in loops.

JSPROP_READONLY
Property is read only.

JSPROP_PERMANENT
Property cannot be deleted.

JSPROP_EXPORTED
Property can be imported by other objects.

JSPROP_INDEX
Property is actually an index into an array of properties, and is cast to a const char *.

If it successfully creates the property, JS_DefinePropertyWithTinyId returns JS_TRUE. If the property already exists, or cannot be created, it returns JS_FALSE.

Notes

While you can assign a setProperty method to a property and set flags to JSPROP_READONLY, the setter method will not be called on this property.

JavaScript-1.5 Reference

Summary

Syntax

Description

Notes

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