feat: Implement update step graphQL mutation

packages/backend/src/graphql/mutations/update-step.ts

@@ -0,0 +1,48 @@
+import { GraphQLInt, GraphQLString, GraphQLNonNull } from 'graphql';
+import Flow from '../../models/flow';
+import Step from '../../models/step';
+import flowType from '../types/flow';
+import stepType from '../types/step';
+import availableAppsEnumType from '../types/available-apps-enum-type';
+import RequestWithCurrentUser from '../../types/express/request-with-current-user';
+
+type Params = {
+  id: number,
+  flowId: number,
+  key: string,
+  appKey: string,
+  connectionId: number
+}
+const updateStepResolver = async (params: Params, req: RequestWithCurrentUser) => {
+  const flow = await Flow.query().findOne({
+    user_id: req.currentUser.id,
+    id: params.flowId
+  }).throwIfNotFound();
+
+  let step = await Step.query().findOne({
+    flow_id: flow.id,
+    id: params.id
+  }).throwIfNotFound();
+
+  step = await step.$query().patchAndFetch({
+    ...step,
+    key: params.key,
+    appKey: params.appKey,
+    connectionId: params.connectionId
+  })
+
+  return step;
+}
+
+const updateStep = {
+  type: stepType,
+  args: {
+    id: { type: GraphQLNonNull(GraphQLInt) },
+    flowId: { type: GraphQLNonNull(GraphQLInt) },
+    key: { type: GraphQLString },
+    appKey: { type: availableAppsEnumType },
+  },
+  resolve: (_: any, params: Params, req: RequestWithCurrentUser) => updateStepResolver(params, req)
+};
+
+export default updateStep;