Web-Related Terms Beginning with U
Unary Operator in JavaScript
Unary operators are operators that accept only one operand. Typical examples are the typeof and unary plus operators.
Uncontrolled Component (ReactJS)
An uncontrolled component is a component whose form's data React does not control exclusively.
undefined in JavaScript
JavaScript automatically assigns undefined to any variable you declare without an initial value.
Unicode
Unicode is a character encoding organization that assigns code points (unique identification numbers) to virtually all the characters in the world.
Unicode (RegExp)
Regular expression's Unicode flag (u) tells the computer to search for Unicode RegExp patterns.
Unit
A unit is anything accepted as a gauge for expressing the quantity or size of another thing.
Unit Test (TDD)
A unit test is a test written to assess the functionality of an independent piece of program.
Unmounting Phase (ReactJS)
A component's unmounting phase is when the component's instance is being removed from the DOM.
unshift() in JavaScript
unshift() adds its arguments to the beginning of its calling array and returns the calling array's new length.
Updating Phase (ReactJS)
A component's updating phase is the period when the component instance is being updated.
URL (Uniform Resource Locator)
A URL is a website's specific location on the web.
User Interface (UI)
A user interface (UI) is a connection mechanism that allows communication between humans and computers.
UTF
UTF (Unicode Transformation Format) is the algorithm Unicode uses to transform all Unicode code points into their equivalent binary formats.
UTF-8
UTF-8 allows encoding code points into code units of eight bits.
UTF-16
UTF-16 allows encoding code points into code units of 16 bits.
UTF-32
UTF-32 allows encoding code points into code units of 32 bits.