The reactive tag refers to a variable type and environment used inside Shiny applications based in the R programming language. Reactive elements are dynamic and changing over time usually due to user input to the Shiny application. This tag should be used with questions and errors regarding how to refresh, update, assign, and access user inputs into Shiny. The reactive tag is to be used in conjunction with the r and shiny tag.

`qmake`, part of the Qt framework, is a tool for generating Makefiles and IDE project files.

A checksum or hash sum is a fixed-size datum computed from an arbitrary block of digital data for the purpose of detecting accidental errors that may have been introduced during its transmission or storage. The integrity of the data can be checked at any later time by recomputing the checksum and comparing it with the stored one.

A design pattern in which an object, called the subject, maintains a list of its dependents, called observers and notifies them automatically of any state changes, usually by calling one of their methods. It is one of the Gang of Four's behavioral design patterns. When using this tag on implementation heavy questions - tag the code language the implementation is written in.

A set of utilities and controls, created by Yahoo in JavaScript and CSS, for building richly interactive web applications using techniques such as DOM scripting, DHTML and AJAX

A statement that the values of two expressions are equal indicated by the sign = .

A ternary operator is any operator that takes three arguments. For the ternary conditional operator " ? :" use the tag [tag:conditional-operator]. Also include the appropriate language tag.

Is a generic term for the act of transmitting files over a computer network or the Internet.

An UI effect where an element or group of elements move over a surface while maintaining smooth continuous contact.

Google Translate is a paid statistical machine translation service provided by Google Inc. to translate a section of text, document or webpage, into another language.

Facebook's SDK for developing Facebook-connected applications for iOS devices