MutationObserver.md

MutationObserver

Namespace: SpawnDev.SpawnJS.JSObjects
Inherits: SpawnJSObject
Source: JSObjects/MutationObserver.cs
MDN Reference: MutationObserver on MDN

The MutationObserver interface provides the ability to watch for changes being made to the DOM tree. It is designed as a replacement for the older Mutation Events feature, which was part of the DOM3 Events specification. https://developer.mozilla.org/en-US/docs/Web/API/MutationObserver

Constructors

Signature	Description
MutationObserver(ActionCallback<Array<MutationRecord>, MutationObserver> callback)	Creates a new instance of MutationObserver
MutationObserver(SpawnJSObjectReference _ref)	Deserialization constructor

Methods

Method	Return Type	Description
Disconnect()	void	Stops the MutationObserver instance from receiving further notifications until and unless observe() is called again.
Observe(Node target, MutationObserveOptions options)	void	Configures the MutationObserver to begin receiving notifications through its callback function when DOM changes matching the given options occur. A DOM Node (which may be an Element) within the DOM tree to watch for changes, or to be the root of a subtree of nodes to be watched. An object providing options that describe which DOM mutations should be reported to mutationObserver's callback. At a minimum, one of childList, attributes, and/or characterData must be true when you call observe(). Otherwise, a TypeError exception will be thrown.
TakeRecords()	MutationRecord[]	Removes all pending notifications from the MutationObserver's notification queue and returns them in a new Array of MutationRecord objects.

Example

// Create the callback for mutation notifications
using var callback = Callback.Create<Array<MutationRecord>, MutationObserver>(
    (mutations, observer) =>
    {
        using var mutationList = mutations;
        foreach (using var mutation in mutationList.ToArray())
        {
            string type = mutation.Type;
            if (type == "childList")
            {
                Console.WriteLine("A child node was added or removed.");
            }
            else if (type == "attributes")
            {
                Console.WriteLine($"Attribute '{mutation.AttributeName}' was modified.");
            }
        }
    });

// Create the MutationObserver
using var observer = new MutationObserver(callback);

// Get the target node to observe
using var document = JS.Get<Document>("document");
using var targetNode = document.GetElementById("some-id");

// Start observing with options
observer.Observe(targetNode, new MutationObserveOptions
{
    Attributes = true,
    ChildList = true,
    Subtree = true
});

// Later, take any pending records
var records = observer.TakeRecords();

// Stop observing
observer.Disconnect();