process.release An Object containing metadata related to the current release, including URLs for the source tarball and headers-only tarball. process.release contains the following properties: name: a string with a value that will always be 'node' for Node.js. For legacy io.js releases, this will be 'io.js'. sourceUrl: a complete URL pointing to a .tar.gz file containing the source of the current release. headersUrl: a complete URL pointing to a .tar.gz file containing only the header file

vm.createContext([sandbox]) If given a sandbox object, will "contextify" that sandbox so that it can be used in calls to vm.runInContext() or script.runInContext(). Inside scripts run as such, sandbox will be the global object, retaining all its existing properties but also having the built-in objects and functions any standard global object has. Outside of scripts run by the vm module, sandbox will be unchanged. If not given a sandbox object, returns a new, empty contextified sandbox object y

message.httpVersion In case of server request, the HTTP version sent by the client. In the case of client response, the HTTP version of the connected-to server. Probably either '1.1' or '1.0'. Also message.httpVersionMajor is the first integer and message.httpVersionMinor is the second.

os.freemem() Returns the amount of free system memory in bytes.

os.platform() Returns the operating system platform. Possible values are 'darwin', 'freebsd', 'linux', 'sunos' or 'win32'. Returns the value of process.platform.

util.isDate(object) Stability: 0 - Deprecated Returns true if the given "object" is a Date. Otherwise, returns false. const util = require('util'); util.isDate(new Date()) // true util.isDate(Date()) // false (without 'new' returns a String) util.isDate({}) // false

net.isIPv4(input) Returns true if input is a version 4 IP address, otherwise returns false.

fs.fstat(fd, callback) Asynchronous fstat(2). The callback gets two arguments (err, stats) where stats is a fs.Stats object. fstat() is identical to stat(), except that the file to be stat-ed is specified by the file descriptor fd.

tlsSocket.remoteAddress The string representation of the remote IP address. For example, '74.125.127.100' or '2001:4860:a005::68'.

Event: 'error' This event is the same as the one provided by child_process.fork(). In a worker you can also use process.on('error').