publishReplay ..... 80 share ..... 81 catchError ..... 82 retry ..... 83 RxJS — Working with Subscription ..... 85 count() operator ..... 85 RxJS — Working with Subjects ..... 86 Create a subject with the observable i.e. the source interacts for an example button click, Http request, etc. ## Subscription When the observable is created, to execute the observable we need to subscribe to it. It can functionality goes for subject too. ## Schedulers A scheduler controls the execution of when the subscription has to start and notified. ## When to use RxJS? If your project consists of lots of async task

p8_1.jpg) ## List of Features ## rclnodejs ROS node -- create/destroy ROS nodes Publisher/Subscription -- send/receive ROS message • Client/Service -- write client/service of ROS request • QoS support utilities -- check if it meets rules Logging -- easier debugging ## ros2-web-bridge Publisher/Subscription -- send/receive msg in browser • Client/Service -- write client/service of ROS request in browser [Image](/uploads/documents/6/7/a/b/67abdd0cd10b767af5278372746f79e1/p12_1.jpg) ## Code Example: Publisher/Subscription rclnodejs.init().then(() => { const node = rclnodejs.createNode('example');

the JMS world). There can be many subscriptions on a topic, a subscription is just another word for a consumer of a topic. Each subscription receives a copy of each message sent to the topic. This differs in receiving news items – each one creates a subscription and the messaging system ensures that a copy of each news message is delivered to each subscription. ## Delivery guarantees A key feature of most that the message will be delivered once and only once to each consumer of a queue or each durable subscription of a topic, even in the event of system failure. This is crucial for many businesses; e.g. you

the JMS world). There can be many subscriptions on a topic, a subscription is just another word for a consumer of a topic. Each subscription receives a copy of each message sent to the topic. This differs in receiving news items – each one creates a subscription and the messaging system ensures that a copy of each news message is delivered to each subscription. ## Delivery guarantees A key feature of most that the message will be delivered once and only once to each consumer of a queue or each durable subscription of a topic, even in the event of system failure. This is crucial for many businesses; e.g. you

the JMS world). There can be many subscriptions on a topic, a subscription is just another word for a consumer of a topic. Each subscription receives a copy of each message sent to the topic. This differs in receiving news items – each one creates a subscription and the messaging system ensures that a copy of each news message is delivered to each subscription. ## Delivery guarantees A key feature of most that the message will be delivered once and only once to each consumer of a queue or each durable subscription of a topic, even in the event of system failure. This is crucial for many businesses; e.g. you

the JMS world). There can be many subscriptions on a topic, a subscription is just another word for a consumer of a topic. Each subscription receives a copy of each message sent to the topic. This differs in receiving news items – each one creates a subscription and the messaging system ensures that a copy of each news message is delivered to each subscription. ## Delivery guarantees A key feature of most that the message will be delivered once and only once to each consumer of a queue or each durable subscription of a topic, even in the event of system failure. This is crucial for many businesses; e.g. you

the JMS world). There can be many subscriptions on a topic, a subscription is just another word for a consumer of a topic. Each subscription receives a copy of each message sent to the topic. This differs in receiving news items - each one creates a subscription and the messaging system ensures that a copy of each news message is delivered to each subscription. ## Delivery guarantees A key feature of most that the message will be delivered once and only once to each consumer of a queue or each durable subscription of a topic, even in the event of system failure. This is crucial for many businesses; e.g. you

the JMS world). There can be many subscriptions on a topic, a subscription is just another word for a consumer of a topic. Each subscription receives a copy of each message sent to the topic. This differs in receiving news items – each one creates a subscription and the messaging system ensures that a copy of each news message is delivered to each subscription. ## Delivery guarantees A key feature of most that the message will be delivered once and only once to each consumer of a queue or each durable subscription of a topic, even in the event of system failure. This is crucial for many businesses; e.g. you

the JMS world). There can be many subscriptions on a topic, a subscription is just another word for a consumer of a topic. Each subscription receives a copy of each message sent to the topic. This differs in receiving news items - each one creates a subscription and the messaging system ensures that a copy of each news message is delivered to each subscription. ## Delivery guarantees A key feature of most that the message will be delivered once and only once to each consumer of a queue or each durable subscription of a topic, even in the event of system failure. This is crucial for many businesses; e.g. you

the JMS world). There can be many subscriptions on a topic, a subscription is just another word for a consumer of a topic. Each subscription receives a copy of each message sent to the topic. This differs in receiving news items - each one creates a subscription and the messaging system ensures that a copy of each news message is delivered to each subscription. ## Delivery guarantees A key feature of most that the message will be delivered once and only once to each consumer of a queue or each durable subscription of a topic, even in the event of system failure. This is crucial for many businesses; e.g. you