I added some nodes to already created graph then i load that graph again , my added nodes get removed .Is it possible to retain those added nodes even after clicking load button ?
In that sample the user needs to click “Save” if they want “Load” to restore the current state of the model.
Are you asking about how to automatically save so that there is no need to have a “Save” command? If so, just implement a Model Changed listener that checks for ModelChanged.isTransactionFinished and then saves the model.
https://gojs.net/latest/intro/changedEvents.html#SavingModelWhenTransactionsComplete
https://gojs.net/latest/intro/usingModels.html#SavingAndLoadingModels