Implement User Task plugin

Fixes #351

src/designer/elsa-workflows-studio/src/plugins/user-task-plugin.tsx

@@ -0,0 +1,24 @@
+import {ElsaPlugin} from "../services/elsa-plugin";
+import {eventBus} from '../services/event-bus';
+import {ActivityDesignDisplayContext, EventTypes, SyntaxNames} from "../models";
+import {h} from "@stencil/core";
+import {parseJson} from "../utils/utils";
+
+export class UserTaskPlugin implements ElsaPlugin {
+  constructor() {
+    eventBus.on(EventTypes.ActivityDesignDisplaying, this.onActivityDesignDisplaying);
+  }
+
+  onActivityDesignDisplaying(context: ActivityDesignDisplayContext) {
+    const activityModel = context.activityModel;
+    
+    if (activityModel.type !== 'UserTask')
+      return;
+
+    const props = activityModel.properties || [];
+    const syntax = SyntaxNames.Json;
+    const branches = props.find(x => x.name == 'Actions') || {expressions: {'Json': '[]'}, syntax: syntax};
+    const expression = branches.expressions[syntax];
+    context.outcomes = !!expression['$values'] ? expression['$values'] : parseJson(expression) || [];
+  }
+}

src/designer/elsa-workflows-studio/src/services/plugin-manager.ts

@@ -14,6 +14,7 @@ import {StartAtPlugin} from "../plugins/start-at-plugin";
 import {CronPlugin} from "../plugins/cron-plugin";
 import {SignalReceivedPlugin} from "../plugins/signal-received-plugin";
 import {SendSignalPlugin} from "../plugins/send-signal-plugin";
+import {UserTaskPlugin} from "../plugins/user-task-plugin";
 
 export class PluginManager {
 
@@ -35,6 +36,7 @@ export class PluginManager {
       new SendSignalPlugin(),
       new WriteLinePlugin(),
       new RunJavascriptPlugin(),
+      new UserTaskPlugin(),
       new SendEmailPlugin()
     ];
   }