QScriptValueIterator Class | Qt Script

Qt 5.14 | Qt Script | C++ Classes | QScriptValueIterator

Qt 5.14.1 Reference Documentation

# QScriptValueIterator Class

The QScriptValueIterator class provides a Java-style iterator for QScriptValue. More...

Header: | #include <QScriptValueIterator>
qmake: | QT += script
Since: | Qt 4.3

This class was introduced in Qt 4.3.

- List of all members, including inherited members

## Public Functions

| QScriptValueIterator(const QScriptValue &object)
QScriptValueIterator & | operator=(QScriptValue &object)
| ~QScriptValueIterator()
QScriptValue::PropertyFlags | flags() const
bool | hasNext() const
bool | hasPrevious() const
QString | name() const
void | next()
void | previous()
void | remove()
QScriptString | scriptName() const
void | setValue(const QScriptValue &value)
void | toBack()
void | toFront()
QScriptValue | value() const

## Detailed Description

The QScriptValueIterator constructor takes a QScriptValue as argument. After construction, the iterator is located at the very beginning of the sequence of properties. Here's how to iterate over all the properties of a QScriptValue:

      QScriptValue object;
      ...
      QScriptValueIterator it(object);
      while (it.hasNext()) {
          it.next();
          qDebug() << it.name() << ": " << it.value().toString();
      }

The next() advances the iterator. The name(), value() and flags() functions return the name, value and flags of the last item that was jumped over.

If you want to remove properties as you iterate over the QScriptValue, use remove(). If you want to modify the value of a property, use setValue().

Note that QScriptValueIterator only iterates over the QScriptValue's own properties; i.e. it does not follow the prototype chain. You can use a loop like this to follow the prototype chain:

      QScriptValue obj = ...; // the object to iterate over
      while (obj.isObject()) {
          QScriptValueIterator it(obj);
          while (it.hasNext()) {
              it.next();
              qDebug() << it.name();
          }
          obj = obj.prototype();
      }

Note that QScriptValueIterator will not automatically skip over properties that have the QScriptValue::SkipInEnumeration flag set; that flag only affects iteration in script code. If you want, you can skip over such properties with code like the following:

      while (it.hasNext()) {
          it.next();
          if (it.flags() & QScriptValue::SkipInEnumeration)
              continue;
          qDebug() << "found enumerated property:" << it.name();
      }

See also QScriptValue::property().

## Member Function Documentation

### QScriptValueIterator::QScriptValueIterator(const QScriptValue &object)

Constructs an iterator for traversing object. The iterator is set to be at the front of the sequence of properties (before the first property).

### QScriptValueIterator &QScriptValueIterator::operator=(QScriptValue &object)

Makes the iterator operate on object. The iterator is set to be at the front of the sequence of properties (before the first property).

### QScriptValueIterator::~QScriptValueIterator()

Destroys the iterator.

### QScriptValue::PropertyFlags QScriptValueIterator::flags() const

Returns the flags of the last property that was jumped over using next() or previous().

See also value().

### bool QScriptValueIterator::hasNext() const

Returns true if there is at least one item ahead of the iterator (i.e. the iterator is not at the back of the property sequence); otherwise returns false.

See also next() and hasPrevious().

### bool QScriptValueIterator::hasPrevious() const

Returns true if there is at least one item behind the iterator (i.e. the iterator is not at the front of the property sequence); otherwise returns false.

See also previous() and hasNext().

### QString QScriptValueIterator::name() const

Returns the name of the last property that was jumped over using next() or previous().

See also value() and flags().

### void QScriptValueIterator::next()

Advances the iterator by one position.

Calling this function on an iterator located at the back of the container leads to undefined results.

See also hasNext(), previous(), and name().

### void QScriptValueIterator::previous()

Moves the iterator back by one position.

Calling this function on an iterator located at the front of the container leads to undefined results.

See also hasPrevious(), next(), and name().

### void QScriptValueIterator::remove()

Removes the last property that was jumped over using next() or previous().

See also setValue().

### QScriptString QScriptValueIterator::scriptName() const

Returns the name of the last property that was jumped over using next() or previous().

This function was introduced in Qt 4.4.

### void QScriptValueIterator::setValue(const QScriptValue &value)

Sets the value of the last property that was jumped over using next() or previous().

See also value() and name().

### void QScriptValueIterator::toBack()

Moves the iterator to the back of the QScriptValue (after the last property).

See also toFront() and previous().

### void QScriptValueIterator::toFront()

Moves the iterator to the front of the QScriptValue (before the first property).

See also toBack() and next().

### QScriptValue QScriptValueIterator::value() const

Returns the value of the last property that was jumped over using next() or previous().

See also setValue() and name().