Method definition is a shorter syntax for defining a function property in an object initializer. It can also be used in classes.

A character class matches any character in or not in a custom set of characters. When the v flag is enabled, it can also be used to match finite-length strings.

The export declaration is used to export values from a JavaScript module. Exported values can then be imported into other programs with the import declaration or dynamic import. The value of an imported binding is subject to change in the module that exports it — when a module updates the value of a binding that it exports, the update will be visible in its imported value.

The clip-path presentation attribute defines or associates a clipping path with the element it is related to.

A regular expression (regex for short) allow developers to match strings against a pattern, extract submatch information, or simply test if the string conforms to that pattern. Regular expressions are used in many programming languages, and JavaScript's syntax is inspired by Perl.

The dx attribute indicates a shift along the x-axis on the position of an element or its content.

Static initialization blocks are declared within a class. It contains statements to be evaluated during class initialization. This permits more flexible initialization logic than static properties, such as using try...catch or setting multiple fields from a single value. Initialization is performed in the context of the current class declaration, with access to private state, which allows the class to share information of its private properties with other classes or functions declared in the same scope (analogous to "friend" classes in C++).

The cx attribute define the x-axis coordinate of a center point.

The spread (...) syntax allows an iterable, such as an array or string, to be expanded in places where zero or more arguments (for function calls) or elements (for array literals) are expected. In an object literal, the spread syntax enumerates the properties of an object and adds the key-value pairs to the object being created.

The less than (<) operator returns true if the left operand is less than the right operand, and false otherwise.