The horiz-adv-x attribute indicates the horizontal advance after rendering a glyph in horizontal orientation.

The JavaScript exception "unlabeled break must be inside loop or switch" occurs when a break statement is not inside a loop or a switch statement.

The JavaScript exception "use of super property/member accesses only valid within methods or eval code within methods" occurs when the super.x or super[x] syntax is used outside of a method.

Below, you'll find a list of errors which are thrown by JavaScript. These errors can be a helpful debugging aid, but the reported problem isn't always immediately clear. The pages below will provide additional details about these errors. Each error is an object based upon the Error object, and has a name and a message.

The font-variant attribute indicates whether the text is to be rendered using variations of the font's glyphs.

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 async function declaration creates a binding of a new async function to a given name. The await keyword is permitted within the function body, enabling asynchronous, promise-based behavior to be written in a cleaner style and avoiding the need to explicitly configure promise chains.

The break statement terminates the current loop or switch statement and transfers program control to the statement following the terminated statement. It can also be used to jump past a labeled statement when used within that labeled statement.

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.

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++).