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Class

ViewTreeWalker (engine/view)

@ckeditor/ckeditor5-engine/src/view/treewalker

class
See source

Position iterator class. It allows to iterate forward and backward over the document.

Filtering

Properties

  • readonly

    boundaries : null | ViewRange

    See source

    Iterator boundaries.

    When the iterator is walking 'forward' on the end of boundary or is walking 'backward' on the start of boundary, then { done: true } is returned.

    If boundaries are not defined they are set before first and after last child of the root node.

  • readonly

    direction : ViewTreeWalkerDirection

    See source

    Walking direction. Defaults 'forward'.

  • readonly

    ignoreElementEnd : boolean

    See source

    Flag indicating whether iterator should ignore elementEnd tags. If set to true, walker will not return a parent node of the start position. Each ViewElement will be returned once. When set to false each element might be returned twice: for 'elementStart' and 'elementEnd'.

  • readonly

    position : ViewPosition

    See source

    Iterator position. If start position is not defined then position depends on direction. If direction is 'forward' position starts form the beginning, when direction is 'backward' position starts from the end.

  • readonly

    shallow : boolean

    See source

    Flag indicating whether iterator should enter elements or not. If the iterator is shallow child nodes of any iterated node will not be returned along with elementEnd tag.

  • readonly

    singleCharacters : boolean

    See source

    Flag indicating whether all characters from ViewText should be returned as one ViewText or one by one as ViewTextProxy.

  • private readonly

    _boundaryEndParent : null | ViewNode | ViewDocumentFragment

    See source

    End boundary parent.

  • private readonly

    _boundaryStartParent : null | ViewNode | ViewDocumentFragment

    See source

    Start boundary parent.

  • private

    _position : ViewPosition

    See source

    Iterator position. If start position is not defined then position depends on direction. If direction is 'forward' position starts form the beginning, when direction is 'backward' position starts from the end.

Methods

  • constructor( options )

    See source

    Creates a range iterator. All parameters are optional, but you have to specify either boundaries or startPosition.

    Parameters

    options : ViewTreeWalkerOptions

    Object with configuration.

    Defaults to {}

  • Symbol.iterator() → IterableIterator<ViewTreeWalkerValue>

    See source

    Iterable interface.

    Returns

    IterableIterator<ViewTreeWalkerValue>

  • jumpTo( position ) → void

    See source

    Moves tree walker position to provided position. Tree walker will continue traversing from that position.

    Note: in contrary to skip, this method does not iterate over the nodes along the way. It simply sets the current tree walker position to a new one. From the performance standpoint, it is better to use jumpTo rather than skip.

    If the provided position is before the start boundary, the position will be set to the start boundary. If the provided position is after the end boundary, the position will be set to the end boundary. This is done to prevent the treewalker from traversing outside the boundaries.

    Parameters

    position : ViewPosition

    Position to jump to.

    Returns

    void

  • next() → IteratorResult<ViewTreeWalkerValue, undefined>

    See source

    Gets the next tree walker's value.

    Returns

    IteratorResult<ViewTreeWalkerValue, undefined>

    Object implementing iterator interface, returning information about taken step.

  • skip( skip ) → void

    See source

    Moves position in the direction skipping values as long as the callback function returns true.

    For example:

    walker.skip( value => value.type == 'text' ); // <p>{}foo</p> -> <p>foo[]</p>
walker.skip( value => true ); // Move the position to the end: <p>{}foo</p> -> <p>foo</p>[]
walker.skip( value => false ); // Do not move the position.

    Parameters

    skip : ( value: ViewTreeWalkerValue ) => boolean

    Callback function. Gets ViewTreeWalkerValue and should return true if the value should be skipped or false if not.

    Returns

    void

  • private

    _formatReturnValue( type, item, previousPosition, nextPosition, [ length ] ) → IteratorYieldResult<ViewTreeWalkerValue>

    See source

    Format returned data and adjust previousPosition and nextPosition if reach the bound of the ViewText.

    Parameters

    type : ViewTreeWalkerValueType

    Type of step.

    item : ViewItem

    Item between old and new position.

    previousPosition : ViewPosition

    Previous position of iterator.

    nextPosition : ViewPosition

    Next position of iterator.

    [ length ] : number

    Length of the item.

    Returns

    IteratorYieldResult<ViewTreeWalkerValue>

  • private

    _next() → IteratorResult<ViewTreeWalkerValue, undefined>

    See source

    Makes a step forward in view. Moves the position to the next position and returns the encountered value.

    Returns

    IteratorResult<ViewTreeWalkerValue, undefined>

  • private

    _previous() → IteratorResult<ViewTreeWalkerValue, undefined>

    See source

    Makes a step backward in view. Moves the position to the previous position and returns the encountered value.

    Returns

    IteratorResult<ViewTreeWalkerValue, undefined>