Replace workflow defaultNotifiers with enhancer transition middleware

Author: CarsonF

src/components/project/workflow/project-workflow.ts

@@ -12,11 +12,8 @@ import {
   BackToActive,
   ResolveParams,
 } from './transitions/dynamic-step';
-import {
-  EmailDistro,
-  FinancialApprovers,
-  TeamMembers,
-} from './transitions/notifiers';
+import { ImplicitlyNotifyTeamMembers } from './transitions/enhancers';
+import { EmailDistro, FinancialApprovers } from './transitions/notifiers';
 
 // This also controls the order shown in the UI.
 // Therefore, these should generally flow down.
@@ -38,7 +35,9 @@ export const ProjectWorkflow = defineWorkflow({
   states: Step,
   event: ProjectWorkflowEvent,
   context: defineContext<ResolveParams>,
-  defaultNotifiers: [TeamMembers],
+  transitionEnhancers: [
+    ImplicitlyNotifyTeamMembers, //
+  ],
 })({
   // In Development
   // region

src/components/project/workflow/transitions/enhancers.ts

@@ -0,0 +1,11 @@
+import { TransitionEnhancer } from '../../../workflow/define-workflow';
+import { ProjectStep as Step } from '../../dto';
+import { ResolveParams } from './dynamic-step';
+import { TeamMembers } from './notifiers';
+
+type Enhancer = TransitionEnhancer<Step, ResolveParams>;
+
+export const ImplicitlyNotifyTeamMembers: Enhancer = (transition) => ({
+  ...transition,
+  notifiers: transition.notifiers.concat(TeamMembers),
+});

src/components/workflow/define-workflow.ts

@@ -1,4 +1,4 @@
-import { many, mapValues, setOf } from '@seedcompany/common';
+import { entries, many, setOf } from '@seedcompany/common';
 import * as uuid from 'uuid';
 import {
   EnumType,
@@ -10,7 +10,6 @@ import {
   ResourceShape,
 } from '~/common';
 import { WorkflowEvent } from './dto';
-import { TransitionNotifier } from './transitions/notifiers';
 import { InternalTransition, TransitionInput } from './transitions/types';
 
 export const defineWorkflow =
@@ -34,33 +33,31 @@ export const defineWorkflow =
      */
     context: () => Context;
     /**
-     * Notifiers that apply to all transitions by default.
+     * Middleware functions to adapt built transitions.
      */
-    defaultNotifiers?: ReadonlyArray<TransitionNotifier<Context>>;
+    transitionEnhancers?: Many<TransitionEnhancer<State, Context>>;
   }) =>
   <TransitionNames extends string>(
     obj: Record<TransitionNames, TransitionInput<State, Context>>,
   ) => {
-    const transitions = mapValues(
-      obj,
-      (
-        name,
-        transition,
-      ): InternalTransition<State, TransitionNames, Context> => ({
+    const enhancers = many(input.transitionEnhancers ?? []);
+
+    const transitions = entries(obj).map(([name, transition]) => {
+      const normalized: InternalTransition<State, TransitionNames, Context> = {
         name,
         ...transition,
         from: transition.from ? setOf(many(transition.from)) : undefined,
         key: (transition.key ?? uuid.v5(name, input.id)) as ID,
         conditions: maybeMany(transition.conditions) ?? [],
-        notifiers: [
-          ...(input.defaultNotifiers ?? []),
-          ...(maybeMany(transition.notifiers) ?? []),
-        ],
-      }),
-    ).asRecord as Record<
-      TransitionNames,
-      InternalTransition<State, TransitionNames, Context>
-    >;
+        notifiers: maybeMany(transition.notifiers) ?? [],
+      };
+      const enhanced = enhancers.reduce(
+        (t, enhancer) => enhancer(t),
+        normalized,
+      );
+      return enhanced;
+    });
+
     const workflow: Workflow<
       Name,
       Context,
@@ -71,7 +68,7 @@ export const defineWorkflow =
     > = {
       ...input,
       id: input.id as ID,
-      transitions: Object.values(transitions),
+      transitions,
       eventResource: input.event,
       transitionByKey: (key: ID) => {
         const transition = workflow.transitions.find((t) => t.key === key);
@@ -137,3 +134,7 @@ export interface Workflow<
     ...keys: Array<Many<Names>>
   ) => ReadonlySet<Names>;
 }
+
+export type TransitionEnhancer<State extends string, Context> = (
+  transition: InternalTransition<State, any, Context>,
+) => InternalTransition<State, any, Context>;