**Dziennik osobisty, wpis z wtorku**
Podczas przerwy postan# @n1ru4l/graphql-live-query-patch
> JSON patch live query executor.
When having a live query executor we want to minimize the data we are sending to the client as much as possible. This executor utilizes JSON patches (https://tools.ietf.org/html/rfc6902) for sending the patches to the client.
## Install
„`bash
npm install -S @n1ru4l/graphql-live-query @n1ru4l/graphql-live-query-patch
„`
## Usage
### Server
„`ts
import { InMemoryLiveQueryStore } from „@n1ru4l/graphql-live-query”;
import { applyLiveQueryJSONPatchDelta } from „@n1ru4l/graphql-live-query-patch”;
import { GraphQLLiveDirective } from „@n1ru4l/graphql-live-query”;
import { execute } from „graphql”;
const liveQueryStore = new InMemoryLiveQueryStore();
const result = await execute({
schema: yourSchema, // make sure your schema has the GraphQLLiveDirective
operationDocument: yourOperationDocument,
variableValues: yourVariableValues,
rootValue: yourRootValue,
contextValue: yourContextValue,
});
// check if live query
if (result.extensions?.liveQuery) {
const asyncIterable = liveQueryStore.execute({
operationDocument: yourOperationDocument,
variableValues: yourVariableValues,
contextValue: yourContextValue,
rootValue: yourRootValue,
});
return applyLiveQueryJSONPatchDelta(asyncIterable);
}
return result;
„`
### Client
On the client we need to apply the patches to the initial result.
„`ts
import { applyJSONPatch } from „@n1ru4l/graphql-live-query-patch”;
function subscribeToLiveUpdates() {
fetch(„http://endpoint”, {
/* opions */
})
.then((response) => response.json())
.then((initialResult) => {
let currentValue = initialResult;
const eventSource = new EventSource(
„http://endpoint/live-query-updates-channel”
);
eventSource.onmessage = (event) => {
const patchPayload = JSON.parse(event.data);
currentValue = applyJSONPatch(currentValue, patchPayload);
};
});
}
„`
