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Mutation Engines

Mutation engines can be synchronous or asynchronous and provide services which are unnecessary for queries.

For asynchronous engines it is necessary to set a global state provider which will make use of Node's executionAsyncId() to differentiate client requests.

Notifications​

Mutaion engines generate notifications which are delivered via functions defined by Subscriptions.

Rollback on Error​

Passing the parameter { rollbackOnError: true } to any engine function will revert shared state in the event of function error.

Global State Provider​

For synchronous engines it is unnecessary to set a global state provider.

An example asyncGlobalState provider is found in 'src/examples/asyneEngine'.

import { globalState: { setStateProvider }} from 'tods-competition-factory';

setStateProvider(asyncGlobalState);