JavaScript-accessible methods
A template is a blueprint for JavaScript functions and objects in a context. You can use a template to wrap C++ functions and data structures within JavaScript objects so that they can be manipulated from JavaScript. See the V8 Embedders Guide section on Templates for further information.
In order to expose functionality to JavaScript via a template, you must provide it to V8 in a form that it understands. Across the versions of V8 supported by NAN, JavaScript-accessible method signatures vary widely, NAN fully abstracts method declaration and provides you with an interface that is similar to the most recent V8 API but is backward-compatible with older versions that still use the now-deceased v8::Argument
type.
Method argument types
Method declarations
Nan::FunctionCallbackInfo
Nan::FunctionCallbackInfo
should be used in place of v8::FunctionCallbackInfo
, even with older versions of Node where v8::FunctionCallbackInfo
does not exist.
Definition:
See the v8::FunctionCallbackInfo
documentation for usage details on these. See Nan::ReturnValue
for further information on how to set a return value from methods.
Nan::PropertyCallbackInfo
Nan::PropertyCallbackInfo
should be used in place of v8::PropertyCallbackInfo
, even with older versions of Node where v8::PropertyCallbackInfo
does not exist.
Definition:
See the v8::PropertyCallbackInfo
documentation for usage details on these. See Nan::ReturnValue
for further information on how to set a return value from property accessor methods.
Nan::ReturnValue
Nan::ReturnValue
is used in place of v8::ReturnValue
on both Nan::FunctionCallbackInfo
and Nan::PropertyCallbackInfo
as the return type of GetReturnValue()
.
Example usage:
Definition:
See the documentation on v8::ReturnValue
for further information on this.
Method declaration
JavaScript-accessible methods should be declared with the following signature to form a Nan::FunctionCallback
:
Example:
You do not need to declare a new HandleScope
within a method as one is implicitly created for you.
Example usage
A helper macro NAN_METHOD(methodname)
exists, compatible with NAN v1 method declarations.
Example usage with NAN_METHOD(methodname)
Use Nan::SetPrototypeMethod
to attach a method to a JavaScript function prototype or Nan::SetMethod
to attach a method directly on a JavaScript object.
Getter declaration
JavaScript-accessible getters should be declared with the following signature to form a Nan::GetterCallback
:
Example:
You do not need to declare a new HandleScope
within a getter as one is implicitly created for you.
A helper macro NAN_GETTER(methodname)
exists, compatible with NAN v1 method declarations.
Also see the V8 Embedders Guide documentation on Accessors.
Setter declaration
JavaScript-accessible setters should be declared with the following signature to form a Nan::SetterCallback
:
Example:
You do not need to declare a new HandleScope
within a setter as one is implicitly created for you.
A helper macro NAN_SETTER(methodname)
exists, compatible with NAN v1 method declarations.
Also see the V8 Embedders Guide documentation on Accessors.
Property getter declaration
JavaScript-accessible property getters should be declared with the following signature to form a Nan::PropertyGetterCallback
:
Example:
You do not need to declare a new HandleScope
within a property getter as one is implicitly created for you.
A helper macro NAN_PROPERTY_GETTER(methodname)
exists, compatible with NAN v1 method declarations.
Also see the V8 Embedders Guide documentation on named property Interceptors.
Property setter declaration
JavaScript-accessible property setters should be declared with the following signature to form a Nan::PropertySetterCallback
:
Example:
You do not need to declare a new HandleScope
within a property setter as one is implicitly created for you.
A helper macro NAN_PROPERTY_SETTER(methodname)
exists, compatible with NAN v1 method declarations.
Also see the V8 Embedders Guide documentation on named property Interceptors.
Property enumerator declaration
JavaScript-accessible property enumerators should be declared with the following signature to form a Nan::PropertyEnumeratorCallback
:
Example:
You do not need to declare a new HandleScope
within a property enumerator as one is implicitly created for you.
A helper macro NAN_PROPERTY_ENUMERATOR(methodname)
exists, compatible with NAN v1 method declarations.
Also see the V8 Embedders Guide documentation on named property Interceptors.
Property deleter declaration
JavaScript-accessible property deleters should be declared with the following signature to form a Nan::PropertyDeleterCallback
:
Example:
You do not need to declare a new HandleScope
within a property deleter as one is implicitly created for you.
A helper macro NAN_PROPERTY_DELETER(methodname)
exists, compatible with NAN v1 method declarations.
Also see the V8 Embedders Guide documentation on named property Interceptors.
Property query declaration
JavaScript-accessible property query methods should be declared with the following signature to form a Nan::PropertyQueryCallback
:
Example:
You do not need to declare a new HandleScope
within a property query method as one is implicitly created for you.
A helper macro NAN_PROPERTY_QUERY(methodname)
exists, compatible with NAN v1 method declarations.
Also see the V8 Embedders Guide documentation on named property Interceptors.
Index getter declaration
JavaScript-accessible index getter methods should be declared with the following signature to form a Nan::IndexGetterCallback
:
Example:
You do not need to declare a new HandleScope
within a index getter as one is implicitly created for you.
A helper macro NAN_INDEX_GETTER(methodname)
exists, compatible with NAN v1 method declarations.
Also see the V8 Embedders Guide documentation on indexed property Interceptors.
Index setter declaration
JavaScript-accessible index setter methods should be declared with the following signature to form a Nan::IndexSetterCallback
:
Example:
You do not need to declare a new HandleScope
within a index setter as one is implicitly created for you.
A helper macro NAN_INDEX_SETTER(methodname)
exists, compatible with NAN v1 method declarations.
Also see the V8 Embedders Guide documentation on indexed property Interceptors.
Index enumerator declaration
JavaScript-accessible index enumerator methods should be declared with the following signature to form a Nan::IndexEnumeratorCallback
:
Example:
You do not need to declare a new HandleScope
within a index enumerator as one is implicitly created for you.
A helper macro NAN_INDEX_ENUMERATOR(methodname)
exists, compatible with NAN v1 method declarations.
Also see the V8 Embedders Guide documentation on indexed property Interceptors.
Index deleter declaration
JavaScript-accessible index deleter methods should be declared with the following signature to form a Nan::IndexDeleterCallback
:
Example:
You do not need to declare a new HandleScope
within a index deleter as one is implicitly created for you.
A helper macro NAN_INDEX_DELETER(methodname)
exists, compatible with NAN v1 method declarations.
Also see the V8 Embedders Guide documentation on indexed property Interceptors.
Index query declaration
JavaScript-accessible index query methods should be declared with the following signature to form a Nan::IndexQueryCallback
:
Example:
You do not need to declare a new HandleScope
within a index query method as one is implicitly created for you.
A helper macro NAN_INDEX_QUERY(methodname)
exists, compatible with NAN v1 method declarations.
Also see the V8 Embedders Guide documentation on indexed property Interceptors.
Nan::SetMethod()
Sets a method with a given name directly on a JavaScript object where the method has the Nan::FunctionCallback
signature (see Method declaration).
Signature:
Nan::SetPrototypeMethod()
Sets a method with a given name on a FunctionTemplate
's prototype where the method has the Nan::FunctionCallback
signature (see Method declaration).
Signature:
Nan::SetAccessor()
Sets getters and setters for a property with a given name on an ObjectTemplate
or a plain Object
. Accepts getters with the Nan::GetterCallback
signature (see Getter declaration) and setters with the Nan::SetterCallback
signature (see Setter declaration).
Signature:
See the V8 ObjectTemplate#SetAccessor()
and Object#SetAccessor()
for further information about how to use Nan::SetAccessor()
.
Nan::SetNamedPropertyHandler()
Sets named property getters, setters, query, deleter and enumerator methods on an ObjectTemplate
. Accepts:
Property getters with the
Nan::PropertyGetterCallback
signature (see Property getter declaration)Property setters with the
Nan::PropertySetterCallback
signature (see Property setter declaration)Property query methods with the
Nan::PropertyQueryCallback
signature (see Property query declaration)Property deleters with the
Nan::PropertyDeleterCallback
signature (see Property deleter declaration)Property enumerators with the
Nan::PropertyEnumeratorCallback
signature (see Property enumerator declaration)
Signature:
See the V8 ObjectTemplate#SetNamedPropertyHandler()
for further information about how to use Nan::SetNamedPropertyHandler()
.
Nan::SetIndexedPropertyHandler()
Sets indexed property getters, setters, query, deleter and enumerator methods on an ObjectTemplate
. Accepts:
Indexed property getters with the
Nan::IndexGetterCallback
signature (see Index getter declaration)Indexed property setters with the
Nan::IndexSetterCallback
signature (see Index setter declaration)Indexed property query methods with the
Nan::IndexQueryCallback
signature (see Index query declaration)Indexed property deleters with the
Nan::IndexDeleterCallback
signature (see Index deleter declaration)Indexed property enumerators with the
Nan::IndexEnumeratorCallback
signature (see Index enumerator declaration)
Signature:
See the V8 ObjectTemplate#SetIndexedPropertyHandler()
for further information about how to use Nan::SetIndexedPropertyHandler()
.
Nan::SetTemplate()
Adds properties on an Object
's or Function
's template.
Signature:
Calls the Template
's Set()
.
Nan::SetPrototypeTemplate()
Adds properties on an Object
's or Function
's prototype template.
Signature:
Calls the FunctionTemplate
's PrototypeTemplate's Set()
.
Nan::SetInstanceTemplate()
Use to add instance properties on FunctionTemplate
's.
Signature:
Calls the FunctionTemplate
's InstanceTemplate's Set()
.
Nan::SetCallHandler()
Set the call-handler callback for a v8::FunctionTemplate
. This callback is called whenever the function created from this FunctionTemplate is called.
Signature:
Calls the FunctionTemplate
's SetCallHandler()
.
Nan::SetCallAsFunctionHandler()
Sets the callback to be used when calling instances created from the v8::ObjectTemplate
as a function. If no callback is set, instances behave like normal JavaScript objects that cannot be called as a function.
Signature:
Calls the ObjectTemplate
's SetCallAsFunctionHandler()
.
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