The QJSValue class acts as a container for Qt/JavaScript data types. More...

#include <qjsvalue.h>

Collaboration diagram for QJSValue:

Public Types
enum	SpecialValue { NullValue , UndefinedValue }
	This enum is used to specify a single-valued type. More...

enum	ErrorType { NoError , GenericError , EvalError , RangeError , ReferenceError , SyntaxError , TypeError , URIError }

enum	ObjectConversionBehavior { ConvertJSObjects , RetainJSObjects }
	This enum is used to specify how JavaScript objects and symbols without an equivalent native Qt type should be treated when converting to QVariant. More...

Public Member Functions
	QJSValue (SpecialValue value=UndefinedValue)
	Constructs a new QJSValue with a special value.

	~QJSValue ()
	Destroys this QJSValue.

	QJSValue (const QJSValue &other)
	Constructs a new QJSValue that is a copy of other.

	QJSValue (QJSValue &&other)
	Move constructor.

QJSValue &	operator= (QJSValue &&other)
	Move-assigns other to this QJSValue object.

	QJSValue (bool value)
	Constructs a new QJSValue with a boolean value.

	QJSValue (int value)
	Constructs a new QJSValue with a number value.

	QJSValue (uint value)
	Constructs a new QJSValue with a number value.

	QJSValue (double value)
	Constructs a new QJSValue with a number value.

	QJSValue (const QString &value)
	Constructs a new QJSValue with a string value.

	QJSValue (const QLatin1String &value)
	Constructs a new QJSValue with a string value.

QT_ASCII_CAST_WARN	QJSValue (const char *str)
	Constructs a new QJSValue with a string value.

QJSValue &	operator= (const QJSValue &other)
	Assigns the other value to this QJSValue.

	QJSValue (QJSPrimitiveValue &&value)

	QJSValue (QJSManagedValue &&value)

bool	isBool () const
	Returns true if this QJSValue is of the primitive type Boolean; otherwise returns false.

bool	isNumber () const
	Returns true if this QJSValue is of the primitive type Number; otherwise returns false.

bool	isNull () const
	Returns true if this QJSValue is of the primitive type Null; otherwise returns false.

bool	isString () const
	Returns true if this QJSValue is of the primitive type String; otherwise returns false.

bool	isUndefined () const
	Returns true if this QJSValue is of the primitive type Undefined or if the managed value has been cleared (by deleting the engine).

bool	isQObject () const
	Returns true if this QJSValue is a QObject; otherwise returns false.

bool	isQMetaObject () const

bool	isObject () const
	Returns true if this QJSValue is of the Object type; otherwise returns false.

bool	isDate () const
	Returns true if this QJSValue is an object of the Date class; otherwise returns false.

bool	isRegExp () const
	Returns true if this QJSValue is an object of the RegExp class; otherwise returns false.

bool	isArray () const
	Returns true if this QJSValue is an object of the Array class; otherwise returns false.

bool	isError () const
	Returns true if this QJSValue is an object of the Error class; otherwise returns false.

bool	isUrl () const
	Returns true if this QJSValue is an object of the URL JavaScript class; otherwise returns false.

QString	toString () const
	Returns the string value of this QJSValue, as defined in \l{ECMA-262} section 9.8, "ToString".

double	toNumber () const
	Returns the number value of this QJSValue, as defined in \l{ECMA-262} section 9.3, "ToNumber".

qint32	toInt () const
	Returns the signed 32-bit integer value of this QJSValue, using the conversion rules described in \l{ECMA-262} section 9.5, "ToInt32".

quint32	toUInt () const
	Returns the unsigned 32-bit integer value of this QJSValue, using the conversion rules described in \l{ECMA-262} section 9.6, "ToUint32".

bool	toBool () const
	Returns the boolean value of this QJSValue, using the conversion rules described in \l{ECMA-262} section 9.2, "ToBoolean".

QVariant	toVariant () const
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Returns toVariant(ConvertJSObjects).

QVariant	toVariant (ObjectConversionBehavior behavior) const
	Returns the QVariant value of this QJSValue, if it can be converted to a QVariant; otherwise returns an invalid QVariant.

QJSPrimitiveValue	toPrimitive () const
	Converts the value to a QJSPrimitiveValue.

QObject *	toQObject () const
	If this QJSValue is a QObject, returns the QObject pointer that the QJSValue represents; otherwise, returns \nullptr.

const QMetaObject *	toQMetaObject () const

QDateTime	toDateTime () const
	Returns a QDateTime representation of this value, in local time.

bool	equals (const QJSValue &other) const
	Returns true if this QJSValue is equal to other, otherwise returns false.

bool	strictlyEquals (const QJSValue &other) const
	Returns true if this QJSValue is equal to other using strict comparison (no conversion), otherwise returns false.

QJSValue	prototype () const
	If this QJSValue is an object, returns the internal prototype ({proto} property) of this object; otherwise returns an undefined QJSValue.

void	setPrototype (const QJSValue &prototype)
	If this QJSValue is an object, sets the internal prototype ({proto} property) of this object to be prototype; if the QJSValue is null, it sets the prototype to null; otherwise does nothing.

QJSValue	property (const QString &name) const
	Returns the value of this QJSValue's property with the given name.

void	setProperty (const QString &name, const QJSValue &value)
	Sets the value of this QJSValue's property with the given name to the given value.

bool	hasProperty (const QString &name) const
	Returns true if this object has a property of the given name, otherwise returns false.

bool	hasOwnProperty (const QString &name) const
	Returns true if this object has an own (not prototype-inherited) property of the given name, otherwise returns false.

QJSValue	property (quint32 arrayIndex) const
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Returns the property at the given arrayIndex.

void	setProperty (quint32 arrayIndex, const QJSValue &value)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Sets the property at the given arrayIndex to the given value.

bool	deleteProperty (const QString &name)
	Attempts to delete this object's property of the given name.

bool	isCallable () const
	Returns true if this QJSValue is a function, otherwise returns false.

QJSValue	call (const QJSValueList &args=QJSValueList()) const
	Calls this QJSValue as a function, passing args as arguments to the function, and using the globalObject() as the "this"-object.

QJSValue	callWithInstance (const QJSValue &instance, const QJSValueList &args=QJSValueList()) const
	Calls this QJSValue as a function, using instance as the ‘this’ object in the function call, and passing args as arguments to the function.

QJSValue	callAsConstructor (const QJSValueList &args=QJSValueList()) const
	Creates a new {Object} and calls this QJSValue as a constructor, using the created object as the ‘this’ object and passing args as arguments.

ErrorType	errorType () const

Friends
class	QJSValuePrivate

Related Symbols
(Note that these are not member symbols.)
	QJSValueList
	This is a typedef for a QList<QJSValue>.

Detailed Description

The QJSValue class acts as a container for Qt/JavaScript data types.

Since: 5.0

\inmodule QtQml

QJSValue supports the types defined in the \l{ECMA-262} standard: The primitive types, which are Undefined, Null, Boolean, Number, and String; and the Object and Array types. Additionally, built-in support is provided for Qt/C++ types such as QVariant and QObject.

For the object-based types (including Date and RegExp), use the newT() functions in QJSEngine (e.g. QJSEngine::newObject()) to create a QJSValue of the desired type. For the primitive types, use one of the QJSValue constructor overloads. For other types, e.g. registered gadget types such as QPoint, you can use QJSEngine::toScriptValue.

The methods named isT() (e.g. isBool(), isUndefined()) can be used to test if a value is of a certain type. The methods named toT() (e.g. toBool(), toString()) can be used to convert a QJSValue to another type. You can also use the generic qjsvalue_cast() function.

Object values have zero or more properties which are themselves QJSValues. Use setProperty() to set a property of an object, and call property() to retrieve the value of a property.

QJSEngine myEngine;
QJSValue myObject = myEngine.newObject();
QJSValue myOtherObject = myEngine.newObject();
myObject.setProperty("myChild", myOtherObject);
myObject.setProperty("name", "John Doe");

If you want to iterate over the properties of a script object, use the QJSValueIterator class.

Object values have an internal {prototype} property, which can be accessed with prototype() and setPrototype().

Function objects (objects for which isCallable()) returns true) can be invoked by calling call(). Constructor functions can be used to construct new objects by calling callAsConstructor().

Use equals() or strictlyEquals() to compare a QJSValue to another.

Note that a QJSValue for which isObject() is true only carries a reference to an actual object; copying the QJSValue will only copy the object reference, not the object itself. If you want to clone an object (i.e. copy an object's properties to another object), you can do so with the help of a {for-in} statement in script code, or QJSValueIterator in C++.

See also: QJSEngine, QJSValueIterator

Definition at line 30 of file qjsvalue.h.

Member Enumeration Documentation

◆ ErrorType

enum QJSValue::ErrorType

Since: 5.12

Use this enum for JavaScript language-specific types of Error objects.

They may be useful when emulating language features in C++ requires the use of specialized exception types. In addition, they may help to more clearly communicate certain typical conditions, instead of throwing a generic JavaScript exception. For example, code that deals with networking and resource locators may find it useful to propagate errors related to malformed locators using the URIError type.

\omitvalue NoError \value GenericError A generic Error object, but not of a specific sub-type. \omitvalue EvalError \value RangeError A value did not match the expected set or range. \value ReferenceError A non-existing variable referenced. \value SyntaxError An invalid token or sequence of tokens was encountered that does not conform with the syntax of the language. \value TypeError An operand or argument is incompatible with the type expected. \value URIError A URI handling function was used incorrectly or the URI provided is malformed.

Enumerator
NoError
GenericError
EvalError
RangeError
ReferenceError
SyntaxError
TypeError
URIError

Definition at line 38 of file qjsvalue.h.

◆ ObjectConversionBehavior

enum QJSValue::ObjectConversionBehavior

This enum is used to specify how JavaScript objects and symbols without an equivalent native Qt type should be treated when converting to QVariant.

\value ConvertJSObjects A best-effort, possibly lossy, conversion is attempted. Symbols are converted to QString.

\value RetainJSObjects The value is retained as QJSValue wrapped in QVariant.

Enumerator
ConvertJSObjects
RetainJSObjects

Definition at line 49 of file qjsvalue.h.

◆ SpecialValue

enum QJSValue::SpecialValue

This enum is used to specify a single-valued type.

\value UndefinedValue An undefined value.

\value NullValue A null value.

Enumerator
NullValue
UndefinedValue

Definition at line 33 of file qjsvalue.h.

Constructor & Destructor Documentation

◆ QJSValue() [1/12]

QJSValue::QJSValue ( SpecialValue value = UndefinedValue )

Constructs a new QJSValue with a special value.

Definition at line 219 of file qjsvalue.cpp.

Referenced by call(), callAsConstructor(), callWithInstance(), property(), property(), and prototype().

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◆ ~QJSValue()

QJSValue::~QJSValue ( )

Destroys this QJSValue.

Definition at line 282 of file qjsvalue.cpp.

References QJSValuePrivate::free().

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◆ QJSValue() [2/12]

QJSValue::QJSValue ( const QJSValue & other )

Constructs a new QJSValue that is a copy of other.

Note that if other is an object (i.e., isObject() would return true), then only a reference to the underlying object is copied into the new script value (i.e., the object itself is not copied).

Definition at line 247 of file qjsvalue.cpp.

References QJSValuePrivate::BoolValue, QJSValuePrivate::DoublePtr, QJSValuePrivate::doublePtr(), QJSValuePrivate::encode(), QJSValuePrivate::IntValue, QJSValuePrivate::Null, QJSValuePrivate::QStringPtr, QJSValuePrivate::qStringPtr(), QJSValuePrivate::QV4ValuePtr, QJSValuePrivate::qv4ValuePtr(), QJSValuePrivate::tag(), and QJSValuePrivate::Undefined.

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◆ QJSValue() [3/12]

QJSValue::QJSValue ( QJSValue && other )

inline

Move constructor.

Moves from other into this QJSValue object.

Definition at line 59 of file qjsvalue.h.

References other().

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◆ QJSValue() [4/12]

QJSValue::QJSValue ( bool value )

Constructs a new QJSValue with a boolean value.

Definition at line 184 of file qjsvalue.cpp.

◆ QJSValue() [5/12]

QJSValue::QJSValue ( int value )

Constructs a new QJSValue with a number value.

Definition at line 191 of file qjsvalue.cpp.

◆ QJSValue() [6/12]

QJSValue::QJSValue ( uint value )

Constructs a new QJSValue with a number value.

Definition at line 198 of file qjsvalue.cpp.

◆ QJSValue() [7/12]

QJSValue::QJSValue ( double value )

Constructs a new QJSValue with a number value.

Definition at line 205 of file qjsvalue.cpp.

◆ QJSValue() [8/12]

QJSValue::QJSValue ( const QString & value )

Constructs a new QJSValue with a string value.

Definition at line 212 of file qjsvalue.cpp.

◆ QJSValue() [9/12]

QJSValue::QJSValue ( const QLatin1String & value )

Constructs a new QJSValue with a string value.

Definition at line 227 of file qjsvalue.cpp.

◆ QJSValue() [10/12]

QJSValue::QJSValue ( const char * str )

Constructs a new QJSValue with a string value.

Definition at line 235 of file qjsvalue.cpp.

◆ QJSValue() [11/12]

QJSValue::QJSValue ( QJSPrimitiveValue && value )

explicit

Definition at line 917 of file qjsvalue.cpp.

References QJSPrimitiveValue::Boolean, QJSPrimitiveValue::Double, QJSValuePrivate::encode(), QJSValuePrivate::encodeNull(), QJSValuePrivate::encodeUndefined(), QJSPrimitiveValue::Integer, QJSPrimitiveValue::Null, QJSPrimitiveValue::String, and QJSPrimitiveValue::Undefined.

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◆ QJSValue() [12/12]

QJSValue::QJSValue ( QJSManagedValue && value )

explicit

Definition at line 943 of file qjsvalue.cpp.

References QJSValuePrivate::adoptPersistentValue(), QJSValuePrivate::encode(), QV4::PersistentValueStorage::free(), and QV4::Encode::undefined().

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Member Function Documentation

◆ call()

QJSValue QJSValue::call ( const QJSValueList & args = QJSValueList() ) const

Calls this QJSValue as a function, passing args as arguments to the function, and using the globalObject() as the "this"-object.

Returns the value returned from the function.

If this QJSValue is not callable, call() does nothing and returns an undefined QJSValue.

Calling call() can cause an exception to occur in the script engine; in that case, call() returns the value that was thrown (typically an {Error} object). You can call isError() on the return value to determine whether an exception occurred.

See also: isCallable(), callWithInstance(), callAsConstructor()

Definition at line 705 of file qjsvalue.cpp.

References QJSValue(), args, QList< T >::at(), QJSValuePrivate::checkEngine(), QJSValuePrivate::convertToReturnedValue(), engine, QJSValuePrivate::engine(), QJSValuePrivate::fromReturnedValue(), QJSEngine::globalObject(), i, QJSEngine::isInterrupted(), QJSEngine::newErrorObject(), Q_ASSERT, QStringLiteral, qWarning, and QList< T >::size().

Referenced by QQuickSpinBoxPrivate::evaluateTextFromValue(), QQuickSpinBoxPrivate::evaluateValueFromText(), QQuickStackView::find(), QQuickTableViewPrivate::getColumnWidth(), and QQuickTableViewPrivate::getRowHeight().

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◆ callAsConstructor()

QJSValue QJSValue::callAsConstructor ( const QJSValueList & args = QJSValueList() ) const

Creates a new {Object} and calls this QJSValue as a constructor, using the created object as the ‘this’ object and passing args as arguments.

If the return value from the constructor call is an object, then that object is returned; otherwise the default constructed object is returned.

If this QJSValue is not a function, callAsConstructor() does nothing and returns an undefined QJSValue.

Calling this function can cause an exception to occur in the script engine; in that case, the value that was thrown (typically an {Error} object) is returned. You can call isError() on the return value to determine whether an exception occurred.

See also: call(), QJSEngine::newObject()

Definition at line 806 of file qjsvalue.cpp.

References QJSValue(), args, QList< T >::at(), QJSValuePrivate::checkEngine(), QJSValuePrivate::convertToReturnedValue(), engine, QJSValuePrivate::engine(), QJSValuePrivate::fromReturnedValue(), i, QJSEngine::isInterrupted(), QJSEngine::newErrorObject(), Q_ASSERT, QStringLiteral, qWarning, and QList< T >::size().

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◆ callWithInstance()

QJSValue QJSValue::callWithInstance	(	const QJSValue &	instance,
		const QJSValueList &	args = QJSValueList() ) const

Calls this QJSValue as a function, using instance as the ‘this’ object in the function call, and passing args as arguments to the function.

Returns the value returned from the function.

If this QJSValue is not a function, call() does nothing and returns an undefined QJSValue.

Note that if instance is not an object, the global object (see \l{QJSEngine::globalObject()}) will be used as the ‘this’ object.

Calling call() can cause an exception to occur in the script engine; in that case, call() returns the value that was thrown (typically an {Error} object). You can call isError() on the return value to determine whether an exception occurred.

See also: call()

Definition at line 754 of file qjsvalue.cpp.

References QJSValue(), args, QList< T >::at(), QJSValuePrivate::checkEngine(), QJSValuePrivate::convertToReturnedValue(), engine, QJSValuePrivate::engine(), QJSValuePrivate::fromReturnedValue(), i, QJSEngine::isInterrupted(), QJSEngine::newErrorObject(), Q_ASSERT, QStringLiteral, qWarning, and QList< T >::size().

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◆ deleteProperty()

bool QJSValue::deleteProperty ( const QString & name )

Attempts to delete this object's property of the given name.

Returns true if the property was deleted, otherwise returns false.

The behavior of this function is consistent with the JavaScript delete operator. In particular:

\list

Non-configurable properties cannot be deleted.
This function will return true even if this object doesn't have a property of the given name (i.e., non-existent properties are "trivially deletable").
If this object doesn't have an own property of the given name, but an object in the prototype() chain does, the prototype object's property is not deleted, and this function returns true. \endlist

See also: setProperty(), hasOwnProperty()

Definition at line 1249 of file qjsvalue.cpp.

References QJSValuePrivate::asReturnedValue(), engine, QJSValuePrivate::engine(), and o.

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◆ equals()

bool QJSValue::equals ( const QJSValue & other ) const

Returns true if this QJSValue is equal to other, otherwise returns false.

The comparison follows the behavior described in \l{ECMA-262} section 11.9.3, "The Abstract Equality Comparison Algorithm".

This function can return true even if the type of this QJSValue is different from the type of the other value; i.e. the comparison is not strict. For example, comparing the number 9 to the string "9" returns true; comparing an undefined value to a null value returns true; comparing a {Number} object whose primitive value is 6 to a {String} object whose primitive value is "6" returns true; and comparing the number 1 to the boolean value {true} returns true. If you want to perform a comparison without such implicit value conversion, use strictlyEquals().

Note that if this QJSValue or the other value are objects, calling this function has side effects on the script engine, since the engine will call the object's valueOf() function (and possibly toString()) in an attempt to convert the object to a primitive value (possibly resulting in an uncaught script exception).

See also: strictlyEquals()

Definition at line 998 of file qjsvalue.cpp.

References QJSValuePrivate::asQString(), QJSValuePrivate::asReturnedValue(), QV4::Runtime::CompareEqual::call(), js_equal(), and other().

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◆ errorType()

QJSValue::ErrorType QJSValue::errorType ( ) const

Since: 5.12 Returns the error type this QJSValue represents if it is an Error object. Otherwise, returns NoError."

See also: isError(), {QJSEngine::Script Exceptions}{QJSEngine - Script Exceptions}

Definition at line 395 of file qjsvalue.cpp.

References error, EvalError, GenericError, NoError, RangeError, ReferenceError, SyntaxError, TypeError, and URIError.

◆ hasOwnProperty()

bool QJSValue::hasOwnProperty ( const QString & name ) const

Returns true if this object has an own (not prototype-inherited) property of the given name, otherwise returns false.

See also: property(), hasProperty()

Definition at line 1291 of file qjsvalue.cpp.

References QJSValuePrivate::asReturnedValue(), QV4::Attr_Invalid, engine, QJSValuePrivate::engine(), and o.

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◆ hasProperty()

bool QJSValue::hasProperty ( const QString & name ) const

Returns true if this object has a property of the given name, otherwise returns false.

See also: property(), hasOwnProperty()

Definition at line 1270 of file qjsvalue.cpp.

References QJSValuePrivate::asReturnedValue(), engine, QJSValuePrivate::engine(), and o.

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◆ isArray()

bool QJSValue::isArray ( ) const

Returns true if this QJSValue is an object of the Array class; otherwise returns false.

See also: QJSEngine::newArray()

Definition at line 425 of file qjsvalue.cpp.

◆ isBool()

bool QJSValue::isBool ( ) const

Returns true if this QJSValue is of the primitive type Boolean; otherwise returns false.

See also: toBool()

Definition at line 293 of file qjsvalue.cpp.

References QJSValuePrivate::BoolValue, and QJSValuePrivate::tag().

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◆ isCallable()

bool QJSValue::isCallable ( ) const

Returns true if this QJSValue is a function, otherwise returns false.

See also: call()

Definition at line 450 of file qjsvalue.cpp.

Referenced by QQuickSpinBoxPrivate::evaluateTextFromValue(), QQuickSpinBoxPrivate::evaluateValueFromText(), QQuickTableViewPrivate::getColumnWidth(), ListLayout::getRoleOrCreate(), QQuickTableViewPrivate::getRowHeight(), QQuickSpinBox::setTextFromValue(), and QQuickSpinBox::setValueFromText().

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◆ isDate()

bool QJSValue::isDate ( ) const

Returns true if this QJSValue is an object of the Date class; otherwise returns false.

Definition at line 1369 of file qjsvalue.cpp.

◆ isError()

bool QJSValue::isError ( ) const

Returns true if this QJSValue is an object of the Error class; otherwise returns false.

See also: errorType(), {QJSEngine::Script Exceptions}{QJSEngine - Script Exceptions}

Definition at line 371 of file qjsvalue.cpp.

◆ isNull()

bool QJSValue::isNull ( ) const

Returns true if this QJSValue is of the primitive type Null; otherwise returns false.

Definition at line 321 of file qjsvalue.cpp.

References QJSValuePrivate::Null, and QJSValuePrivate::tag().

Referenced by QQuickRectangle::setGradient().

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◆ isNumber()

bool QJSValue::isNumber ( ) const

Returns true if this QJSValue is of the primitive type Number; otherwise returns false.

See also: toNumber()

Definition at line 304 of file qjsvalue.cpp.

References QJSValuePrivate::DoublePtr, QJSValuePrivate::IntValue, and QJSValuePrivate::tag().

Referenced by QQuickRectangle::setGradient().

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◆ isObject()

bool QJSValue::isObject ( ) const

Returns true if this QJSValue is of the Object type; otherwise returns false.

Note that function values, variant values, and QObject values are objects, so this function returns true for such values.

See also: QJSEngine::newObject()

Definition at line 439 of file qjsvalue.cpp.

◆ isQMetaObject()

bool QJSValue::isQMetaObject ( ) const

Since: 5.8

Returns true if this QJSValue is a QMetaObject; otherwise returns false.

See also: toQMetaObject(), QJSEngine::newQMetaObject()

Definition at line 1405 of file qjsvalue.cpp.

◆ isQObject()

bool QJSValue::isQObject ( ) const

Returns true if this QJSValue is a QObject; otherwise returns false.

Note: This function returns true even if the QObject that this QJSValue wraps has been deleted.

See also: toQObject(), QJSEngine::newQObject()

Definition at line 1392 of file qjsvalue.cpp.

Referenced by QQuickRectangle::setGradient().

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◆ isRegExp()

bool QJSValue::isRegExp ( ) const

Returns true if this QJSValue is an object of the RegExp class; otherwise returns false.

Definition at line 1378 of file qjsvalue.cpp.

◆ isString()

bool QJSValue::isString ( ) const

Returns true if this QJSValue is of the primitive type String; otherwise returns false.

See also: toString()

Definition at line 332 of file qjsvalue.cpp.

References QJSValuePrivate::QStringPtr, QJSValuePrivate::QV4ValuePtr, QJSValuePrivate::qv4ValuePtr(), and QJSValuePrivate::tag().

Referenced by QQuickRectangle::setGradient().

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◆ isUndefined()

bool QJSValue::isUndefined ( ) const

Returns true if this QJSValue is of the primitive type Undefined or if the managed value has been cleared (by deleting the engine).

Otherwise returns false.

Definition at line 351 of file qjsvalue.cpp.

References QJSValuePrivate::QV4ValuePtr, QJSValuePrivate::qv4ValuePtr(), QJSValuePrivate::tag(), and QJSValuePrivate::Undefined.

Referenced by QQuickTableViewPrivate::getColumnWidth(), QQuickTableViewPrivate::getRowHeight(), QQmlPrivate::isUndefined(), and QQuickRectangle::setGradient().

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◆ isUrl()

bool QJSValue::isUrl ( ) const

Returns true if this QJSValue is an object of the URL JavaScript class; otherwise returns false.

Note: For a QJSValue that contains a QUrl, this function returns false. However, {toVariant().value<QUrl>()} works in both cases.

Definition at line 383 of file qjsvalue.cpp.

◆ operator=() [1/2]

QJSValue & QJSValue::operator= ( const QJSValue & other )

Assigns the other value to this QJSValue.

Note that if other is an object (isObject() returns true), only a reference to the underlying object will be assigned; the object itself will not be copied.

Definition at line 901 of file qjsvalue.cpp.

References QJSValuePrivate::asQString(), QJSValuePrivate::asReturnedValue(), QJSValuePrivate::free(), other(), QJSValuePrivate::setString(), and QJSValuePrivate::setValue().

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◆ operator=() [2/2]

QJSValue & QJSValue::operator= ( QJSValue && other )

inline

Move-assigns other to this QJSValue object.

Definition at line 60 of file qjsvalue.h.

References d, and other().

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◆ property() [1/2]

QJSValue QJSValue::property ( const QString & name ) const

Returns the value of this QJSValue's property with the given name.

If no such property exists, an undefined QJSValue is returned.

If the property is implemented using a getter function (i.e. has the PropertyGetter flag set), calling property() has side-effects on the script engine, since the getter function will be called (possibly resulting in an uncaught script exception). If an exception occurred, property() returns the value that was thrown (typically an {Error} object).

To access array elements, use the \l {QJSValue::}{setProperty(quint32 arrayIndex, const QJSValue &value)} overload instead.

See also: setProperty(), hasProperty(), QJSValueIterator

Definition at line 1072 of file qjsvalue.cpp.

References QJSValue(), QJSValuePrivate::asReturnedValue(), engine, QJSValuePrivate::engine(), QJSValuePrivate::fromReturnedValue(), and o.

Referenced by QQuickColorSpaceValueType::create(), QQuickFontValueType::create(), and setFontProperty().

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◆ property() [2/2]

QJSValue QJSValue::property ( quint32 arrayIndex ) const

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Returns the property at the given arrayIndex.

It is possible to access elements in an array in two ways. The first is to use the array index as the property name:

qDebug() << jsValueArray.property(QLatin1String("4")).toString();

qDebug

#define qDebug

[1]

Definition qlogging.h:164

QLatin1String

QLatin1StringView QLatin1String

Definition qstringfwd.h:31

The second is to use the overload that takes an index:

qDebug() << jsValueArray.property(4).toString();

Both of these approaches achieve the same result, except that the latter:

\list

Is easier to use (can use an integer directly)
Is faster (no conversion to integer) \endlist

If this QJSValue is not an Array object, this function behaves as if property() was called with the string representation of arrayIndex.

Definition at line 1120 of file qjsvalue.cpp.

References QJSValue(), QJSValuePrivate::asReturnedValue(), engine, QJSValuePrivate::engine(), QJSValuePrivate::fromReturnedValue(), and o.

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◆ prototype()

QJSValue QJSValue::prototype ( ) const

If this QJSValue is an object, returns the internal prototype ({proto} property) of this object; otherwise returns an undefined QJSValue.

See also: setPrototype(), isObject()

Definition at line 841 of file qjsvalue.cpp.

References QJSValue(), engine, QJSValuePrivate::engine(), QJSValuePrivate::fromReturnedValue(), NullValue, and o.

Referenced by setPrototype().

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◆ setProperty() [1/2]

void QJSValue::setProperty	(	const QString &	name,
		const QJSValue &	value )

Sets the value of this QJSValue's property with the given name to the given value.

If this QJSValue is not an object, this function does nothing.

If this QJSValue does not already have a property with name name, a new property is created.

To modify array elements, use the \l {QJSValue::}{setProperty(quint32 arrayIndex, const QJSValue &value)} overload instead.

See also: property(), deleteProperty()

Definition at line 1152 of file qjsvalue.cpp.

References QJSValuePrivate::asReturnedValue(), QJSValuePrivate::checkEngine(), QJSValuePrivate::convertToReturnedValue(), engine, QJSValuePrivate::engine(), o, and qWarning.

Referenced by QQuickText::fontInfo(), and main().

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◆ setProperty() [2/2]

void QJSValue::setProperty	(	quint32	arrayIndex,
		const QJSValue &	value )

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Sets the property at the given arrayIndex to the given value.

It is possible to modify elements in an array in two ways. The first is to use the array index as the property name:

jsValueArray.setProperty(QLatin1String("4"), value);

value

EGLOutputLayerEXT EGLint EGLAttrib value

[5]

Definition qeglstreamconvenience_p.h:46

The second is to use the overload that takes an index:

jsValueArray.setProperty(4, value);

Both of these approaches achieve the same result, except that the latter:

\list

Is easier to use (can use an integer directly)
Is faster (no conversion to integer) \endlist

If this QJSValue is not an Array object, this function behaves as if setProperty() was called with the string representation of arrayIndex.

See also: {QJSValue::}{property(quint32 arrayIndex)}, {Working With Arrays}

Definition at line 1206 of file qjsvalue.cpp.

References QJSValuePrivate::asReturnedValue(), QJSValuePrivate::checkEngine(), QJSValuePrivate::convertToReturnedValue(), engine, QJSValuePrivate::engine(), QV4::PropertyKey::fromArrayIndex(), o, and qWarning.

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◆ setPrototype()

void QJSValue::setPrototype ( const QJSValue & prototype )

If this QJSValue is an object, sets the internal prototype ({proto} property) of this object to be prototype; if the QJSValue is null, it sets the prototype to null; otherwise does nothing.

The internal prototype should not be confused with the public property with name "prototype"; the public prototype is usually only set on functions that act as constructors.

See also: prototype(), isObject()

Definition at line 868 of file qjsvalue.cpp.

References QJSValuePrivate::asReturnedValue(), engine, QJSValuePrivate::engine(), QV4::Value::fromReturnedValue(), o, prototype(), and qWarning.

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◆ strictlyEquals()

bool QJSValue::strictlyEquals ( const QJSValue & other ) const

Returns true if this QJSValue is equal to other using strict comparison (no conversion), otherwise returns false.

The comparison follows the behavior described in \l{ECMA-262} section 11.9.6, "The Strict Equality Comparison Algorithm".

If the type of this QJSValue is different from the type of the other value, this function returns false. If the types are equal, the result depends on the type, as shown in the following table:

\table \header

Type
Result \row
Undefined
true \row
Null
true \row
Boolean
true if both values are true, false otherwise \row
Number
false if either value is NaN (Not-a-Number); true if values are equal, false otherwise \row
String
true if both values are exactly the same sequence of characters, false otherwise \row
Object
true if both values refer to the same object, false otherwise \endtable

See also: equals()

Definition at line 1035 of file qjsvalue.cpp.

References QJSValuePrivate::asQString(), QJSValuePrivate::asReturnedValue(), other(), and QV4::RuntimeHelpers::strictEqual().

Referenced by QQuickTableViewPrivate::compareModel(), QQuickTableView::setColumnWidthProvider(), and QQuickTableView::setRowHeightProvider().

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◆ toBool()

bool QJSValue::toBool ( ) const

Returns the boolean value of this QJSValue, using the conversion rules described in \l{ECMA-262} section 9.2, "ToBoolean".

Note that if this QJSValue is an object, calling this function has side effects on the script engine, since the engine will call the object's valueOf() function (and possibly toString()) in an attempt to convert the object to a primitive value (possibly resulting in an uncaught script exception).

See also: isBool()

Definition at line 546 of file qjsvalue.cpp.

References QJSValuePrivate::asQString(), and QV4::Value::toBoolean().

Referenced by QQuickFontValueType::create().

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◆ toDateTime()

QDateTime QJSValue::toDateTime ( ) const

Returns a QDateTime representation of this value, in local time.

If this QJSValue is not a date, or the value of the date is NaN (Not-a-Number), an invalid QDateTime is returned.

See also: isDate()

Definition at line 1358 of file qjsvalue.cpp.

References date.

◆ toInt()

qint32 QJSValue::toInt ( ) const

Returns the signed 32-bit integer value of this QJSValue, using the conversion rules described in \l{ECMA-262} section 9.5, "ToInt32".

Note that if this QJSValue is an object, calling this function has side effects on the script engine, since the engine will call the object's valueOf() function (and possibly toString()) in an attempt to convert the object to a primitive value (possibly resulting in an uncaught script exception).

See also: toNumber(), toUInt()

Definition at line 566 of file qjsvalue.cpp.

References QJSValuePrivate::asQString(), QV4::RuntimeHelpers::stringToNumber(), and QV4::Value::toInt32().

Referenced by QQuickSpinBoxPrivate::evaluateValueFromText(), and QQuickRectangle::setGradient().

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◆ toNumber()

double QJSValue::toNumber ( ) const

Returns the number value of this QJSValue, as defined in \l{ECMA-262} section 9.3, "ToNumber".

Note that if this QJSValue is an object, calling this function has side effects on the script engine, since the engine will call the object's valueOf() function (and possibly toString()) in an attempt to convert the object to a primitive value (possibly resulting in an uncaught script exception).

See also: isNumber(), toInt(), toUInt()

Definition at line 526 of file qjsvalue.cpp.

References QJSValuePrivate::asQString(), QV4::RuntimeHelpers::stringToNumber(), and QV4::Value::toNumber().

Referenced by QQuickTableViewPrivate::getColumnWidth(), QQuickTableViewPrivate::getRowHeight(), and main().

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◆ toPrimitive()

QJSPrimitiveValue QJSValue::toPrimitive ( ) const

Converts the value to a QJSPrimitiveValue.

If the value holds a type supported by QJSPrimitiveValue, the value is copied. Otherwise the value is converted to a string, and the string is stored in QJSPrimitiveValue.

Note: Conversion of a managed value to a string can throw an exception. In particular, symbols cannot be coerced into strings, or a custom toString() method may throw. In this case the result is the undefined value and the engine carries an error after the conversion.

Definition at line 681 of file qjsvalue.cpp.

References QJSValuePrivate::asQString(), QJSValuePrivate::asReturnedValue(), QV4::ExecutionEngine::createPrimitive(), and QV4::Value::fromReturnedValue().

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◆ toQMetaObject()

const QMetaObject * QJSValue::toQMetaObject ( ) const

Since: 5.8

If this QJSValue is a QMetaObject, returns the QMetaObject pointer that the QJSValue represents; otherwise, returns \nullptr.

See also: isQMetaObject()

Definition at line 1337 of file qjsvalue.cpp.

References QJSValuePrivate::asReturnedValue(), engine, QJSValuePrivate::engine(), and wrapper().

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◆ toQObject()

QObject * QJSValue::toQObject ( ) const

If this QJSValue is a QObject, returns the QObject pointer that the QJSValue represents; otherwise, returns \nullptr.

If the QObject that this QJSValue wraps has been deleted, this function returns \nullptr (i.e. it is possible for toQObject() to return \nullptr even when isQObject() returns true).

See also: isQObject()

Definition at line 1316 of file qjsvalue.cpp.

References QJSValuePrivate::asReturnedValue(), engine, QJSValuePrivate::engine(), and wrapper().

Referenced by QQuickRectangle::setGradient().

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◆ toString()

QString QJSValue::toString ( ) const

Returns the string value of this QJSValue, as defined in \l{ECMA-262} section 9.8, "ToString".

Note that if this QJSValue is an object, calling this function has side effects on the script engine, since the engine will call the object's toString() function (and possibly valueOf()) in an attempt to convert the object to a primitive value (possibly resulting in an uncaught script exception).

See also: isString()

Definition at line 494 of file qjsvalue.cpp.

References QJSValuePrivate::asQString(), QJSValuePrivate::asReturnedValue(), and QV4::Value::fromReturnedValue().

Referenced by QQuickSpinBoxPrivate::evaluateTextFromValue(), QuickTestResult::fuzzyCompare(), and QQuickRectangle::setGradient().

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◆ toUInt()

quint32 QJSValue::toUInt ( ) const

Returns the unsigned 32-bit integer value of this QJSValue, using the conversion rules described in \l{ECMA-262} section 9.6, "ToUint32".

Note that if this QJSValue is an object, calling this function has side effects on the script engine, since the engine will call the object's valueOf() function (and possibly toString()) in an attempt to convert the object to a primitive value (possibly resulting in an uncaught script exception).

See also: toNumber(), toInt()

Definition at line 586 of file qjsvalue.cpp.

References QJSValuePrivate::asQString(), QV4::RuntimeHelpers::stringToNumber(), and QV4::Value::toUInt32().

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◆ toVariant() [1/2]

QVariant QJSValue::toVariant ( ) const

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Returns toVariant(ConvertJSObjects).

See also: isVariant()

Definition at line 601 of file qjsvalue.cpp.

References ConvertJSObjects, and toVariant().

Referenced by toVariant().

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◆ toVariant() [2/2]

QVariant QJSValue::toVariant ( QJSValue::ObjectConversionBehavior behavior ) const

Returns the QVariant value of this QJSValue, if it can be converted to a QVariant; otherwise returns an invalid QVariant.

Some JavaScript types and objects have native expressions in Qt. Those are converted to their native expressions. For example:

\table \header

Input Type
Result \row
Undefined
An invalid QVariant. \row
Null
A QVariant containing a null pointer (QMetaType::Nullptr). \row
Boolean
A QVariant containing the value of the boolean. \row
Number
A QVariant containing the value of the number. \row
String
A QVariant containing the value of the string. \row
QVariant Object
The result is the QVariant value of the object (no conversion). \row
QObject Object
A QVariant containing a pointer to the QObject. \row
Date Object
A QVariant containing the date value (toDateTime()). \row
RegularExpression Object
A QVariant containing the regular expression value. \endtable

For other types the behavior parameter is relevant. If ConvertJSObjects is given, a best effort but possibly lossy conversion is attempted. Generic JavaScript objects are converted to QVariantMap. JavaScript arrays are converted to QVariantList. Each property or element is converted to a QVariant, recursively; cyclic references are not followed. JavaScript function objects are dropped. If RetainJSObjects is given, the QJSValue is wrapped into a QVariant via QVariant::fromValue(). The resulting conversion is lossless but the internal structure of the objects is not immediately accessible.

See also: isVariant()

Definition at line 637 of file qjsvalue.cpp.

References QJSValuePrivate::asQString(), QJSValuePrivate::asReturnedValue(), QV4::Value::fromReturnedValue(), Q_ASSERT, RetainJSObjects, QV4::ExecutionEngine::toVariant(), and QV4::ExecutionEngine::toVariantLossy().

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Friends And Related Symbol Documentation

◆ QJSValueList()

QJSValueList

Definition at line 22 of file qjsvalue.h.

◆ QJSValuePrivate

friend class QJSValuePrivate

friend

Definition at line 135 of file qjsvalue.h.

The documentation for this class was generated from the following files:

qtdeclarative/src/qml/jsapi/qjsvalue.h (eaad950651c237708c26f3931963c633077ace01)
qtdeclarative/src/qml/jsapi/qjsvalue.cpp (59c5038af49b82a8ee9c93455cdf093fa097aec8)

Public Types

Public Member Functions

Friends

Related Symbols

Detailed Description

Member Enumeration Documentation

◆ ErrorType

◆ ObjectConversionBehavior

◆ SpecialValue

Constructor & Destructor Documentation

◆ QJSValue() [1/12]

◆ ~QJSValue()

◆ QJSValue() [2/12]

◆ QJSValue() [3/12]

◆ QJSValue() [4/12]

◆ QJSValue() [5/12]

◆ QJSValue() [6/12]

◆ QJSValue() [7/12]

◆ QJSValue() [8/12]

◆ QJSValue() [9/12]

◆ QJSValue() [10/12]

◆ QJSValue() [11/12]

◆ QJSValue() [12/12]

Member Function Documentation

◆ call()

◆ callAsConstructor()

◆ callWithInstance()

◆ deleteProperty()

◆ equals()

◆ errorType()

◆ hasOwnProperty()

◆ hasProperty()

◆ isArray()

◆ isBool()

◆ isCallable()

◆ isDate()

◆ isError()

◆ isNull()

◆ isNumber()

◆ isObject()

◆ isQMetaObject()

◆ isQObject()

◆ isRegExp()

◆ isString()

◆ isUndefined()

◆ isUrl()

◆ operator=() [1/2]

◆ operator=() [2/2]

◆ property() [1/2]

◆ property() [2/2]

◆ prototype()

◆ setProperty() [1/2]

◆ setProperty() [2/2]

◆ setPrototype()

◆ strictlyEquals()

◆ toBool()

◆ toDateTime()

◆ toInt()

◆ toNumber()

◆ toPrimitive()

◆ toQMetaObject()

◆ toQObject()

◆ toString()

◆ toUInt()

◆ toVariant() [1/2]

◆ toVariant() [2/2]

Friends And Related Symbol Documentation

◆ QJSValueList()

◆ QJSValuePrivate