Add plugin base class

lib/plugin.js

@@ -0,0 +1,7 @@
+module.exports = class Plugin {
+  get api() {
+    const properties = Object.getOwnPropertyNames(this.constructor.prototype);
+    properties.splice(properties.indexOf('constructor'), 1);
+    return properties;
+  }
+};

lib/plugins/issues.js

@@ -1,6 +1,7 @@
 const handlebars = require('handlebars');
+const Plugin = require('../plugin');
 
-module.exports = class IssuesPlugin {
+module.exports = class Issues extends Plugin {
   // checkIfEventApplies(event) {
   //   return event.issue !== undefined || event.pull_request !== undefined;
   // }

lib/workflow.js

@@ -11,16 +11,12 @@ module.exports = class Workflow {
     this.filterFn = () => true;
     this.api = {};
 
+    // Define a new function in the API for each plugin method
     for (const plugin of plugins) {
-      // Get all the property names of the plugin
-      for (const method of Object.getOwnPropertyNames(plugin.constructor.prototype)) {
-        if (method !== 'constructor') {
-          // Define a new function in the API for this plugin method, forcing
-          // the binding to this to prevent any tampering.
+      for (const method of plugin.api) {
         this.api[method] = this.proxy(plugin[method]).bind(this);
       }
     }
-    }
 
     this.api.filter = this.filter.bind(this);
   }

test/plugin.js

@@ -0,0 +1,22 @@
+const expect = require('expect');
+const Plugin = require('../lib/plugin');
+
+class TestPlugin extends Plugin {
+  foo() {
+
+  }
+}
+
+describe('Plugin', () => {
+  const plugin = new TestPlugin();
+
+  describe('api', () => {
+    it('includes methods', () => {
+      expect(plugin.api.indexOf('foo') >= 0).toBe(true);
+    });
+
+    it('exludes constructor', () => {
+      expect(plugin.api.indexOf('constructor')).toBe(-1);
+    });
+  });
+});