Leverage Template literals to replace dot (#1297)

This PR replaces the doT template engine with native JavaScript template literals for generating ROS2 message/service wrapper classes. The change migrates from external template files to pure JavaScript functions, improving maintainability and performance.

- Removed dependency on doT template engine and replaced with native JavaScript template literals
- Created new template generator functions for messages, services, actions, and service events
- Updated the IDL generator to use the new template functions instead of doT templates

**Reference**: 
- https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Template_literals

Fix: #1297

Author: minggangw

package.json

@@ -78,7 +78,6 @@
     "bindings": "^1.5.0",
     "compare-versions": "^6.1.1",
     "debug": "^4.4.0",
-    "dot": "^1.1.3",
     "fs-extra": "^11.2.0",
     "json-bigint": "^1.0.0",
     "node-addon-api": "^8.3.1",

rosidl_gen/idl_generator.js

@@ -14,19 +14,17 @@
 
 'use strict';
 
-const dot = require('dot');
 const fse = require('fs-extra');
 const path = require('path');
 const parser = require('../rosidl_parser/rosidl_parser.js');
 const actionMsgs = require('./action_msgs.js');
 const DistroUtils = require('../lib/distro.js');
+const generateMessage = require('./templates/message-template.js');
+const generateService = require('./templates/service-template.js');
+const generateAction = require('./templates/action-template.js');
+const generateServiceEvent = require('./templates/service-event-template.js');
 
-dot.templateSettings.strip = false;
-dot.log = process.env.RCLNODEJS_LOG_VERBOSE || false;
 const isDebug = !!process.argv.find((arg) => arg === '--debug');
-const dots = dot.process({
-  path: path.join(__dirname, '../rosidl_gen/templates'),
-});
 
 /**
  * Output generated code to disk. Do not overwrite
@@ -53,7 +51,7 @@ async function generateServiceJSStruct(
     '__' +
     serviceInfo.interfaceName +
     '.js';
-  const generatedSrvCode = dots.service({ serviceInfo: serviceInfo });
+  const generatedSrvCode = generateService({ serviceInfo: serviceInfo });
 
   // We are going to only generate the service JavaScript file if it meets one
   // of the followings:
@@ -74,7 +72,7 @@ async function generateServiceJSStruct(
 
 async function generateServiceEventMsg(serviceInfo, dir) {
   const fileName = serviceInfo.interfaceName + '.msg';
-  const generatedEvent = dots.service_event({ serviceInfo: serviceInfo });
+  const generatedEvent = generateServiceEvent({ serviceInfo: serviceInfo });
 
   return writeGeneratedCode(dir, fileName, generatedEvent).then(() => {
     serviceInfo.interfaceName += '_Event';
@@ -107,7 +105,7 @@ async function generateServiceEventJSStruct(msgInfo, dir) {
   // const AddTwoInts_RequestWrapper = require('../../generated/example_interfaces/example_interfaces__srv__AddTwoInts_Request.js');
   // const AddTwoInts_ResponseWrapper = require('../../generated/example_interfaces/example_interfaces__srv__AddTwoInts_Response.js');
   msgInfo.isServiceEvent = true;
-  const generatedCode = dots.message({
+  const generatedCode = generateMessage({
     messageInfo: msgInfo,
     spec: spec,
     json: JSON.stringify(spec, null, '  '),
@@ -135,7 +133,7 @@ function generateMessageJSStructFromSpec(messageInfo, dir, spec) {
     spec.msgName +
     '.js';
 
-  const generatedCode = dots.message({
+  const generatedCode = generateMessage({
     messageInfo: messageInfo,
     spec: spec,
     json: JSON.stringify(spec, null, '  '),
@@ -275,7 +273,7 @@ async function generateActionJSStruct(actionInfo, dir) {
     '__' +
     actionInfo.interfaceName +
     '.js';
-  const generatedCode = dots.action({ actionInfo: actionInfo });
+  const generatedCode = generateAction({ actionInfo: actionInfo });
   dir = path.join(dir, actionInfo.pkgName);
   const action = writeGeneratedCode(dir, fileName, generatedCode);
 

rosidl_gen/templates/action-template.js

@@ -0,0 +1,68 @@
+// Copyright (c) 2025, The Robot Web Tools Contributors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+function generateAction(data) {
+  const actionInfo = data.actionInfo;
+  const className = `${actionInfo.pkgName}__${actionInfo.subFolder}__${actionInfo.interfaceName}`;
+
+  return `// This file is automatically generated by rclnodejs
+//
+// *** DO NOT EDIT directly
+//
+
+'use strict';
+
+class ${className} {
+  static get Goal() {
+    return require('./${className}_Goal.js');
+  }
+
+  static get Result() {
+    return require('./${className}_Result.js');
+  }
+
+  static get Feedback() {
+    return require('./${className}_Feedback.js');
+  }
+
+  static get impl() {
+    return {
+      get SendGoalService() {
+        return require('./${className}_SendGoal.js');
+      },
+      get GetResultService() {
+        return require('./${className}_GetResult.js');
+      },
+      get FeedbackMessage() {
+        return require('./${className}_FeedbackMessage.js');
+      },
+      get CancelGoal() {
+        return require('../action_msgs/action_msgs__srv__CancelGoal.js');
+      },
+      get GoalStatusArray() {
+        return require('../action_msgs/action_msgs__msg__GoalStatusArray.js');
+      }
+    };
+  }
+
+  static type() {
+    return {pkgName: '${actionInfo.pkgName}', subFolder: '${actionInfo.subFolder}', interfaceName: '${actionInfo.interfaceName}'};
+  }
+}
+
+module.exports = ${className};
+`;
+}
+
+module.exports = generateAction;