Module org.htmlunit.corejs

Package org.htmlunit.corejs.javascript

Interface Function

All Superinterfaces:

Callable, Constructable, PropHolder<Scriptable>, Scriptable

All Known Implementing Classes:

BaseFunction, BoundFunction, Delegator, FunctionObject, IdFunctionObject, JSFunction, KnownBuiltInFunction, LambdaConstructor, LambdaFunction, NativeContinuation, NativeFunction, NativeJavaClass, NativeJavaConstructor, NativeJavaMethod, NativeJavaTopPackage, Require, Synchronizer

public interface Function
extends Scriptable, Callable, Constructable

This is interface that all functions in JavaScript must implement. The interface provides for calling functions and constructors.

Author:

Norris Boyd

See Also:

• Scriptable

Field Summary

Fields inherited from interface org.htmlunit.corejs.javascript.Scriptable

NOT_FOUND

Method Summary

Modifier and Type	Method	Description
Object	call(Context cx, VarScope scope, Object thisObj, Object[] args)	Call the function.
Scriptable	construct(Context cx, Object nt, VarScope s, Object[] args)	Call the function as a constructor.
default VarScope	getDeclarationScope()	Return the scope in which this function was declared or closed over.
default boolean	isConstructor()	Return whether this function can be called as a constructor.

Methods inherited from interface org.htmlunit.corejs.javascript.Constructable

construct

Methods inherited from interface org.htmlunit.corejs.javascript.Scriptable

delete, delete, delete, get, get, get, getAncestor, getClassName, getDefaultValue, getIds, getParentScope, getPrototype, has, has, has, hasInstance, put, put, put, setParentScope, setPrototype

Method Details

call

Object call(Context cx,
 VarScope scope,
 Object thisObj,
 Object[] args)

Call the function.

Note that the array of arguments is not guaranteed to have length greater than 0.

Specified by:

call in interface Callable

Parameters:

cx - the current Context for this thread

scope - the scope to execute the function relative to. This is set to the value returned by getParentScope() except when the function is called from a closure.

thisObj - the JavaScript this object

args - the array of arguments

Returns:

the result of the call

construct

Scriptable construct(Context cx,
 Object nt,
 VarScope s,
 Object[] args)

Call the function as a constructor.

This method is invoked by the runtime in order to satisfy a use of the JavaScript new operator. This method is expected to create a new object and return it.

If nt is equal to this then this call is equivalent `new f(...arguments), but reflection and super constructor calls may pass in different values.

Specified by:

construct in interface Constructable

Parameters:

cx - the current Context for this thread

nt - the new.target for this call,

s - an enclosing scope of the caller except when the function is called from a closure.

args - the array of arguments

Returns:

the allocated object

getDeclarationScope

default VarScope getDeclarationScope()

Return the scope in which this function was declared or closed over. This is the "[[Environment]]" defined in https://tc39.es/ecma262/#sec-ecmascript-function-objects. Although this is currently precisely equal to the parent scope (or "__parent__") of an object it is useful to distinguish the two concepts as parent scopes are no longer supported by the spec in general and present a significant barrier to future optimisations.

isConstructor

default boolean isConstructor()

Return whether this function can be called as a constructor.