Operation API
Operation 对象定义了底层指令，用来 Slate 编辑其应用更改到其内部状态。将所有的更改表示为操作是允许 Slate 编辑器轻松实现历史记录、写作和其他功能的原因。
Static methods
Manipulation methods
Operation.inverse(op: Operation) => Operation
Invert an operation, returning a new operation that will exactly undo the original when applied.
Check methods
Operation.isNodeOperation(value: any) => boolean
Check if a value is a NodeOperation object. Returns the value as a NodeOperation if it is one.
Operation.isOperation(value: any) => boolean
Check if a value is an Operation object. Returns the value as an Operation if it is one.
Operation.isOperationList(value: any) => boolean
Check if a value is a list of Operation objects. Returns the value as an Operation[] if it is one.
Operation.isSelectionOperation(value: any) => boolean
Check if a value is a SelectionOperation object. Returns the value as a SelectionOperation if it is one.
Operation.isTextOperation(value: any) => boolean
Check if a value is a TextOperation object. Returns the value as a TextOperation if it is one.