JavaScript supports a compact set of statements, specifically control flow statements, that you can use to incorporate a great deal of interactivity in your application. This chapter provides an overview of these statements.

A closure is the combination of a function bundled together (enclosed) with references to its surrounding state (the lexical environment). In other words, a closure gives you access to an outer function's scope from an inner function. In JavaScript, closures are created every time a function is created, at function creation time.

JavaScript is a prototype-based language — an object's behaviors are specified by its own properties and its prototype's properties. However, with the addition of classes, the creation of hierarchies of objects and the inheritance of properties and their values are much more in line with other object-oriented languages such as Java. In this section, we will demonstrate how objects can be created from classes.

The <feDiffuseLighting> SVG filter primitive lights an image using the alpha channel as a bump map. The resulting image, which is an RGBA opaque image, depends on the light color, light position and surface geometry of the input bump map.

The class expression is one way to define a class. Similar to function expressions, class expressions can be named or unnamed. If named, the name of the class is local to the class body only.

The global isFinite() function determines whether the passed value is a finite number. If needed, the parameter is first converted to a number.

The import() call, commonly called dynamic import, is a function-like expression that allows loading an ECMAScript module asynchronously and dynamically into a potentially non-module environment.

The stroke-linecap attribute is a presentation attribute defining the shape to be used at the end of open subpaths when they are stroked.

The logical AND assignment (x &&= y) operator only assigns if x is truthy.

The strict equality operator (===) checks whether its two operands are equal, returning a Boolean result. Unlike the equality operator, the strict equality operator always considers operands of different types to be different.