ChangesObservable

Description

Initializes the observable with an optional initial index value used as the baseline for generating first-time change events.

Methods

createObserver

Source code

changesObservable.createObserver() ⇒ ChangesObserver

Creates and returns a new instance of the ChangesObserver object. The resource allows subscribing to the index changes that during the code running may change. Changes are emitted as an array of the index change. Each change is represented separately as an object with op, index, oldValue, and newValue props.

For example:

1
[
2
  { op: 'replace', index: 1, oldValue: false, newValue: true },
3
  { op: 'replace', index: 3, oldValue: false, newValue: true },
4
  { op: 'insert', index: 4, oldValue: false, newValue: true },
5
]
6
// or when the new index map changes have less indexes
7
[
8
  { op: 'replace', index: 1, oldValue: false, newValue: true },
9
  { op: 'remove', index: 4, oldValue: false, newValue: true },
10
]

emit

Source code

changesObservable.emit(indexesState)

The method is an entry point for triggering new index map changes. Emitting the changes triggers comparing algorithm which compares last saved state with a new state. When there are some differences, the changes are sent to all subscribers.

Param	Type	Description
indexesState	`Array`	An array with index map state.