The shift() method of Array instances removes the first element from an array and returns that removed element. This method changes the length of the array.

The RegExp object is used for matching text with a pattern.

The Uint8Array typed array represents an array of 8-bit unsigned integers. The contents are initialized to 0 unless initialization data is explicitly provided. Once established, you can reference elements in the array using the object's methods, or using standard array index syntax (that is, using bracket notation).

The class declaration creates a binding of a new class to a given name.

The JavaScript exception "reduce of empty array with no initial value" occurs when a reduce function is used.

The JavaScript exception "malformed URI sequence" occurs when URI encoding or decoding wasn't successful.

This page lists features of JavaScript that are deprecated (that is, still available but planned for removal) and obsolete (that is, no longer usable).

The JavaScript exception "octal escape sequences can't be used in untagged template literals or in strict mode code" occurs when octal escape sequences are used in strict mode string literals or untagged template literals.

The JavaScript strict mode-only exception "is read-only" occurs when a global variable or object property that was assigned to is a read-only property.

Functions are one of the fundamental building blocks in JavaScript. A function in JavaScript is similar to a procedure—a set of statements that performs a task or calculates a value, but for a procedure to qualify as a function, it should take some input and return an output where there is some obvious relationship between the input and the output. To use a function, you must define it somewhere in the scope from which you wish to call it.