There are a number of text conventions used throughout this book.

CodeInText: Indicates code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles. Here is an example: "To install the AWS IoT SDK for JavaScript, you can do so through the npm package."

A block of code is set as follows:

device
   .on('connect', function() {
     console.log('connected');
     device.subscribe('topic_1');
     device.publish('topic_1', JSON.stringify({ test_data: 1}));
   });

When we wish to draw your attention to a particular part of a code block, the relevant lines or items are set in bold:

device
 .on('message', function(topic, payload) {
 console.log('recv:', topic, payload.toString());
});

console.log('Sensor subscriber started.');

Any command-line input or output is written as follows:

$ npm install aws-iot-device-sdk

Bold: Indicates a new term, an important word, or words that you see onscreen. For example, words in menus or dialog boxes appear in the text like this. Here is an example: "You can click on the Get started button in the Configuring a device section".