Interface MutationRecord
addedNodes: NodeList;
attributeName: string;
attributeNamespace: string;
nextSibling: Node;
oldValue: string;
previousSibling: Node;
removedNodes: NodeList;
target: Node;
type: MutationRecordType;
}
 Properties
ReadonlyaddedNodes 
Return the nodes added and removed respectively.
ReadonlyattributeName 
Returns the local name of the changed attribute, and null otherwise.
ReadonlyattributeNamespace 
Returns the namespace of the changed attribute, and null otherwise.
ReadonlynextSibling 
Return the previous and next sibling respectively of the added or removed nodes, and null otherwise.
ReadonlyoldValue 
The return value depends on type. For "attributes", it is the value of the changed attribute before the change. For "characterData", it is the data of the changed node before the change. For "childList", it is null.
ReadonlypreviousSibling 
Return the previous and next sibling respectively of the added or removed nodes, and null otherwise.
ReadonlyremovedNodes 
Return the nodes added and removed respectively.
Readonlytarget
Returns the node the mutation affected, depending on the type. For "attributes", it is the element whose attribute changed. For "characterData", it is the CharacterData node. For "childList", it is the node whose children changed.
Readonlytype
Returns "attributes" if it was an attribute mutation. "characterData" if it was a mutation to a CharacterData node. And "childList" if it was a mutation to the tree of nodes.
A MutationRecord represents an individual DOM mutation. It is the object that is passed to MutationObserver's callback.
MDN Reference