Provide tutorial about basic concepts of ROS2 #1243
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Pull Request Overview
This PR adds a comprehensive tutorial document that introduces the fundamental communication patterns in ROS 2, specifically focusing on Topics (publish/subscribe) and Services (request/response) patterns using the rclnodejs JavaScript library.
- Provides detailed explanations and practical examples for ROS 2 Topics and Services
- Includes complete JavaScript code examples for publishers, subscribers, service servers, and clients
- Offers guidance on when to use Topics vs Services with practical use cases
Tip: Customize your code reviews with copilot-instructions.md. Create the file or learn how to get started.
| setInterval(() => { | ||
| const message = `Hello ROS ${counter}`; | ||
| console.log(`Publishing message: ${message}`); | ||
| publisher.publish(message); |
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The publish method expects a message object with the correct structure for std_msgs/msg/String, but a plain string is being passed. It should be publisher.publish({data: message}); to match the String message type structure.
| publisher.publish(message); | |
| publisher.publish({data: message}); |
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| // Create a subscriber for String messages on 'topic' | ||
| node.createSubscription('std_msgs/msg/String', 'topic', (msg) => { | ||
| console.log(`Received message: ${typeof msg}`, msg); |
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The message object should be accessed as msg.data for std_msgs/msg/String type. Currently logging the entire message object instead of the string content.
| console.log(`Received message: ${typeof msg}`, msg); | |
| console.log(`Received message: ${msg.data}`); |
| a: BigInt(10), | ||
| b: BigInt(15), |
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The use of BigInt for integer values in ROS 2 service requests may not be necessary or correct. Standard JavaScript numbers should typically work for AddTwoInts service. The documentation should clarify when BigInt is required.
| a: BigInt(10), | |
| b: BigInt(15), | |
| a: 10, | |
| b: 15, |
| Received message: string Hello ROS 0 | ||
| Received message: string Hello ROS 1 | ||
| Received message: string Hello ROS 2 |
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The expected output shows 'string Hello ROS 0' but with the correct message structure (msg.data), it should display just 'Hello ROS 0' without the type information.
| Received message: string Hello ROS 0 | |
| Received message: string Hello ROS 1 | |
| Received message: string Hello ROS 2 | |
| Received message: Hello ROS 0 | |
| Received message: Hello ROS 1 | |
| Received message: Hello ROS 2 |
| Incoming request: object { a: 45n, b: 67n } | ||
| Sending response: object { sum: 112n } | ||
| ``` | ||
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| **Service client terminal:** | ||
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| ``` | ||
| Sending: object { a: 45n, b: 67n } | ||
| Result: object { sum: 112n } |
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The expected output shows BigInt values (45n, 67n) but the actual example code uses BigInt(10) and BigInt(15). The expected output should match the input values from the example code.
| Incoming request: object { a: 45n, b: 67n } | |
| Sending response: object { sum: 112n } | |
| ``` | |
| **Service client terminal:** | |
| ``` | |
| Sending: object { a: 45n, b: 67n } | |
| Result: object { sum: 112n } | |
| Incoming request: object { a: 10n, b: 15n } | |
| Sending response: object { sum: 25n } |
Service client terminal:
Sending: object { a: 10n, b: 15n }
Result: object { sum: 25n }
This PR adds a comprehensive tutorial document that introduces the fundamental communication patterns in ROS 2, specifically focusing on Topics (publish/subscribe) and Services (request/response) patterns using the rclnodejs JavaScript library. - Provides detailed explanations and practical examples for ROS 2 Topics and Services - Includes complete JavaScript code examples for publishers, subscribers, service servers, and clients - Offers guidance on when to use Topics vs Services with practical use cases Fix: #1241
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This PR adds a comprehensive tutorial document that introduces the fundamental communication patterns in ROS 2, specifically focusing on Topics (publish/subscribe) and Services (request/response) patterns using the rclnodejs JavaScript library.
Fix: #1241