Support component with event handlers

Fixes #42

Author: simonihmig

lib/__tests__/__snapshots__/transform.js.snap

@@ -559,6 +559,51 @@ foo
 =========="
 `;
 
+exports[`native components handles multiple event handlers correctly 1`] = `
+"==========
+
+      import Component from '@ember/component';
+
+      export default class FooComponent extends Component {
+        mouseDown() {
+          console.log('Hello!');
+        }
+
+        mouseUp() {
+          console.log('World!');
+        }
+      }
+    
+~~~~~~~~~~
+foo
+~~~~~~~~~~
+ => tagName: div
+~~~~~~~~~~
+
+      import { tagName } from \\"@ember-decorators/component\\";
+      import { action } from \\"@ember/object\\";
+      import Component from '@ember/component';
+
+      @tagName(\\"\\")
+      export default class FooComponent extends Component {
+        @action
+        handleMouseDown() {
+          console.log('Hello!');
+        }
+
+        @action
+        handleMouseUp() {
+          console.log('World!');
+        }
+      }
+    
+~~~~~~~~~~
+<div ...attributes {{on \\"mousedown\\" this.handleMouseDown}} {{on \\"mouseup\\" this.handleMouseUp}}>
+  foo
+</div>
+=========="
+`;
+
 exports[`native components handles single \`@classNames\` item correctly 1`] = `
 "==========
 
@@ -589,6 +634,42 @@ foo
 =========="
 `;
 
+exports[`native components handles single event handler correctly 1`] = `
+"==========
+
+      import Component from '@ember/component';
+
+      export default class FooComponent extends Component {
+        click() {
+          console.log('Hello World!');
+        }
+      }
+    
+~~~~~~~~~~
+foo
+~~~~~~~~~~
+ => tagName: div
+~~~~~~~~~~
+
+      import { tagName } from \\"@ember-decorators/component\\";
+      import { action } from \\"@ember/object\\";
+      import Component from '@ember/component';
+
+      @tagName(\\"\\")
+      export default class FooComponent extends Component {
+        @action
+        handleClick() {
+          console.log('Hello World!');
+        }
+      }
+    
+~~~~~~~~~~
+<div ...attributes {{on \\"click\\" this.handleClick}}>
+  foo
+</div>
+=========="
+`;
+
 exports[`native components keeps unrelated decorators in place 1`] = `
 "==========
 

lib/__tests__/transform.js

@@ -457,6 +457,42 @@ describe('native components', function() {
     expect(generateSnapshot(source, template)).toMatchSnapshot();
   });
 
+  test('handles single event handler correctly', () => {
+    let source = `
+      import Component from '@ember/component';
+
+      export default class FooComponent extends Component {
+        click() {
+          console.log('Hello World!');
+        }
+      }
+    `;
+
+    let template = `foo`;
+
+    expect(generateSnapshot(source, template)).toMatchSnapshot();
+  });
+
+  test('handles multiple event handlers correctly', () => {
+    let source = `
+      import Component from '@ember/component';
+
+      export default class FooComponent extends Component {
+        mouseDown() {
+          console.log('Hello!');
+        }
+
+        mouseUp() {
+          console.log('World!');
+        }
+      }
+    `;
+
+    let template = `foo`;
+
+    expect(generateSnapshot(source, template)).toMatchSnapshot();
+  });
+
   test('throws for non-boolean @classNameBindings', () => {
     let source = `
       import Component from '@ember/component';
@@ -538,38 +574,6 @@ describe('native components', function() {
     );
   });
 
-  test('throws if component is using `keyDown()`', () => {
-    let source = `
-      import Component from '@ember/component';
-
-      export default class FooComponent extends Component {
-        keyDown() {
-          console.log('Hello World!');
-        }
-      }
-    `;
-
-    expect(() => transform(source, '')).toThrowErrorMatchingInlineSnapshot(
-      `"Using \`keyDown()\` is not supported in tagless components"`
-    );
-  });
-
-  test('throws if component is using `click()`', () => {
-    let source = `
-      import Component from '@ember/component';
-
-      export default class FooComponent extends Component {
-        click() {
-          console.log('Hello World!');
-        }
-      }
-    `;
-
-    expect(() => transform(source, '')).toThrowErrorMatchingInlineSnapshot(
-      `"Using \`click()\` is not supported in tagless components"`
-    );
-  });
-
   test('multi-line template', () => {
     let source = `
       import Component from '@ember/component';

lib/transform/native.js

@@ -13,6 +13,7 @@ const {
   removeDecorator,
   ensureImport,
   isProperty,
+  renameEventHandler,
 } = require('../utils/native');
 
 const EVENT_HANDLER_METHODS = [
@@ -98,14 +99,6 @@ module.exports = function transformNativeComponent(root, options) {
     throw new SilentError(`Using \`this.elementId\` is not supported in tagless components`);
   }
 
-  // skip components that use `click()` etc.
-  for (let methodName of EVENT_HANDLER_METHODS) {
-    let handlerMethod = classBody.filter(path => isMethod(path, methodName))[0];
-    if (handlerMethod) {
-      throw new SilentError(`Using \`${methodName}()\` is not supported in tagless components`);
-    }
-  }
-
   // analyze `elementId`, `attributeBindings`, `classNames` and `classNameBindings`
   let elementId = findElementId(classBody);
   debug('elementId: %o', elementId);
@@ -119,6 +112,19 @@ module.exports = function transformNativeComponent(root, options) {
   let classNameBindings = findClassNameBindings(classDeclaration);
   debug('classNameBindings: %o', classNameBindings);
 
+  let eventHandlers = new Map();
+  // rename event handlers and add @action
+  for (let eventName of EVENT_HANDLER_METHODS) {
+    let handlerMethod = classBody.filter(path => isMethod(path, eventName))[0];
+
+    if (handlerMethod) {
+      let methodName = renameEventHandler(handlerMethod);
+      addClassDecorator(handlerMethod, 'action');
+      ensureImport(root, 'action', '@ember/object');
+      eventHandlers.set(eventName.toLowerCase(), methodName);
+    }
+  }
+
   // set `@tagName('')`
   addClassDecorator(classDeclaration, 'tagName', [j.stringLiteral('')]);
   ensureImport(root, 'tagName', '@ember-decorators/component');
@@ -142,5 +148,13 @@ module.exports = function transformNativeComponent(root, options) {
 
   let newSource = root.toSource();
 
-  return { newSource, tagName, elementId, classNames, classNameBindings, attributeBindings };
+  return {
+    newSource,
+    tagName,
+    elementId,
+    classNames,
+    classNameBindings,
+    attributeBindings,
+    eventHandlers,
+  };
 };

lib/transform/template.js

@@ -8,7 +8,7 @@ const PLACEHOLDER = '@@@PLACEHOLDER@@@';
 
 module.exports = function transformTemplate(
   template,
-  { tagName, elementId, classNames, classNameBindings, attributeBindings, ariaRole },
+  { tagName, elementId, classNames, classNameBindings, attributeBindings, ariaRole, eventHandlers },
   options
 ) {
   // wrap existing template with root element
@@ -50,11 +50,19 @@ module.exports = function transformTemplate(
   }
   attrs.push(b.attr('...attributes', b.text('')));
 
+  let modifiers = [];
+  if (eventHandlers) {
+    eventHandlers.forEach((methodName, eventName) => {
+      modifiers.push(b.elementModifier('on', [b.string(eventName), b.path(`this.${methodName}`)]));
+    });
+  }
+
   let templateAST = templateRecast.parse(template);
 
   templateAST.body = [
     b.element(tagName, {
       attrs,
+      modifiers,
       children: [b.text(`\n${PLACEHOLDER}\n`)],
     }),
   ];

lib/utils/native.js

@@ -8,11 +8,13 @@ function addClassDecorator(classDeclaration, name, args) {
   if (existing) {
     existing.value.expression.arguments = args;
   } else {
-    if (classDeclaration.value.decorators === undefined) {
+    if (!classDeclaration.value.decorators) {
       classDeclaration.value.decorators = [];
     }
     classDeclaration.value.decorators.unshift(
-      j.decorator(j.callExpression(j.identifier(name), args))
+      args === undefined
+        ? j.decorator(j.identifier(name))
+        : j.decorator(j.callExpression(j.identifier(name), args))
     );
   }
 }
@@ -56,7 +58,7 @@ function findStringProperty(properties, name, defaultValue = null) {
 
 function findDecorator(path, name, withArgs) {
   let decorators = path.get('decorators');
-  if (decorators.value === undefined) {
+  if (!decorators.value) {
     return;
   }
 
@@ -257,6 +259,15 @@ function createImportStatement(source, imported, local) {
   return declaration;
 }
 
+function renameEventHandler(path) {
+  let oldName = path.value.key.name;
+  let newName = `handle${oldName.charAt(0).toUpperCase()}${oldName.slice(1)}`;
+
+  path.value.key.name = newName;
+
+  return newName;
+}
+
 module.exports = {
   addClassDecorator,
   isProperty,
@@ -270,4 +281,5 @@ module.exports = {
   removeDecorator,
   ensureImport,
   removeImport,
+  renameEventHandler,
 };