Conventions

In this book, you will find a number of styles of text that distinguish between different kinds of information. Here are some examples of these styles, and an explanation of their meaning.

Code words in text are shown as follows: "We can include other contexts through the use of the include directive."

A block of code is set as follows:

var zmq  = require('zmq')
var sink = zmq.socket('pull');
sink.bindSync("tcp://*:5001");

sink.on('message', function(buffer) {
  console.log('Message from worker: ', buffer.toString());
});

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

function produce() {
  [...]
  variationsStream(alphabet, maxLength)
    .on('data', function(combination) {
        [...]
        var msg = {searchHash: searchHash, variations: batch};
 channel.sendToQueue('jobs_queue',
 new Buffer(JSON.stringify(msg)));
        [...]
      }
    })
   [...]
}

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

node replier
node requestor

New terms and important words are shown in bold. Words that you see on the screen, in menus or dialog boxes for example, appear in the text like this: "To explain the problem, we will create a little web spider, a command-line application that takes in a web URL as the input and downloads its contents locally into a file."