fix: infer EventEmitter extensions from API (#259)

* fix: infer EventEmitter extensions from API

* chore: update tests

Author: MarshallOfSound

src/module-declaration.ts

@@ -31,12 +31,11 @@ export const generateModuleDeclaration = (
 ) => {
   const moduleAPI = modules[_.upperFirst(module.name)] || [];
   const newModule = !modules[_.upperFirst(module.name)];
-  const isStaticVersion =
-    module.type === 'Module' &&
-    API.some(
-      (tModule, tIndex) =>
-        index !== tIndex && tModule.name.toLowerCase() === module.name.toLowerCase(),
-    );
+  const instanceModuleForStaticVersion = API.find(
+    (tModule, tIndex) =>
+      index !== tIndex && tModule.name.toLowerCase() === module.name.toLowerCase(),
+  );
+  const isStaticVersion = module.type === 'Module' && !!instanceModuleForStaticVersion;
   const isClass = module.type === 'Class' || isStaticVersion;
   const parentModules: ParsedDocumentationResult = [];
   let parentModule:
@@ -53,11 +52,23 @@ export const generateModuleDeclaration = (
   // Interface Declaration
   if (newModule) {
     if (module.type !== 'Structure') {
-      if (utils.isEmitter(module)) {
+      let extendsInfo = '';
+      if (module.extends) {
+        extendsInfo = ` extends ${module.extends}`;
+      } else if (
+        utils.isEmitter(module) ||
+        (isStaticVersion &&
+          instanceModuleForStaticVersion &&
+          utils.isEmitter(instanceModuleForStaticVersion))
+      ) {
+        extendsInfo = ` extends ${isClass ? 'NodeEventEmitter' : 'NodeJS.EventEmitter'}`;
+      }
+      if (module.name.toLowerCase() === 'session' && isStaticVersion) {
+        console.log({ isStaticVersion, instanceModuleForStaticVersion, extendsInfo });
+      }
+      if (extendsInfo) {
         moduleAPI.push(
-          `${isClass ? 'class' : 'interface'} ${_.upperFirst(
-            module.name,
-          )} extends ${module.extends || (isClass ? 'NodeEventEmitter' : 'NodeJS.EventEmitter')} {`,
+          `${isClass ? 'class' : 'interface'} ${_.upperFirst(module.name)}${extendsInfo} {`,
         );
         moduleAPI.push('', `// Docs: ${module.websiteUrl}`, '');
       } else {

src/utils.ts

@@ -8,6 +8,7 @@ import {
   DocumentationBlock,
   DetailedFunctionType,
   DocumentationTag,
+  ParsedDocumentationResult,
 } from '@electron/docs-parser';
 import _ from 'lodash';
 import d from 'debug';
@@ -257,34 +258,30 @@ export const paramify = (paramName: string) => {
   }
   return paramName;
 };
-// TODO: Infer through electron-docs-linter/parser
-export const isEmitter = (module: Pick<ModuleDocumentationContainer, 'name'>) => {
-  const nonEventEmitters = [
-    'menuitem',
-    'nativeimage',
-    'shell',
-    'browserview',
-    'webrequest',
-    'crashreporter',
-    'dock',
-    'commandline',
-    'browserwindowproxy',
-    'clipboard',
-    'contenttracing',
-    'desktopcapturer',
-    'dialog',
-    'globalshortcut',
-    'powersaveblocker',
-    'touchbar',
-    'touchbarbutton',
-    'net',
-    'netlog',
-    'protocol',
-    'contextbridge',
-    'webframe',
-    'messagechannelmain',
-  ];
-  return !nonEventEmitters.includes(module.name.toLowerCase());
+export const isEmitter = (doc: ParsedDocumentationResult[0]) => {
+  // Is a module, has events, is an eventemitter
+  if (doc.type === 'Module' && doc.events.length) {
+    return true;
+  }
+
+  // Is a class, has instance events, is an eventemitter
+  if (doc.type === 'Class' && doc.instanceEvents.length) {
+    return true;
+  }
+
+  // Implements the on and removeListener methods normally means
+  // it's an EventEmitter wrapper like ipcMain or ipcRenderer
+  const relevantMethods =
+    doc.type === 'Class' ? doc.instanceMethods : doc.type === 'Module' ? doc.methods : [];
+  if (
+    relevantMethods.find(m => m.name === 'on') &&
+    relevantMethods.find(m => m.name === 'removeListener')
+  ) {
+    return true;
+  }
+
+  // Structure and Elements are not eventemitters, so bail here
+  return false;
 };
 export const isPrimitive = (type: string) => {
   const primitives = ['boolean', 'number', 'any', 'string', 'void', 'unknown'];

test/utils_spec.js

@@ -116,11 +116,18 @@ describe('utils', () => {
 
   describe('isEmitter', () => {
     it('should return true on most modules', () => {
-      expect(utils.isEmitter({ name: 'app' })).to.eq(true);
+      expect(utils.isEmitter({ name: 'app', type: 'Module', events: [1] })).to.eq(true);
     });
 
     it('should return false for specific non-emitter modules', () => {
-      expect(utils.isEmitter({ name: 'menuitem' })).to.eq(false);
+      expect(
+        utils.isEmitter({
+          name: 'menuitem',
+          type: 'Class',
+          instanceEvents: [],
+          instanceMethods: [],
+        }),
+      ).to.eq(false);
     });
   });