This page introduces the basic infrastructure of the JavaScript runtime environment. The model is largely theoretical and abstract, without any platform-specific or implementation-specific details. Modern JavaScript engines heavily optimize the described semantics.

The Object.entries() static method returns an array of a given object's own enumerable string-keyed property key-value pairs.

A unique identifier for a running thread.

The find() method of TypedArray instances returns the first element in the provided typed array that satisfies the provided testing function. If no values satisfy the testing function, undefined is returned. This method has the same algorithm as Array.prototype.find().

The stroke-width attribute is a presentation attribute defining the width of the stroke to be applied to the shape. It applies to any SVG shape or text-content element, but as an inherited property, it may be applied to elements such as <g> and still have the intended effect on descendant elements' strokes.

A type that is composed of other types.

The text-decoration attribute defines whether text is decorated with an underline, overline and/or strike-through. It is a shorthand for the text-decoration-line and text-decoration-style properties.

A handle to the standard input stream of a process.

The JavaScript exception "TypeError: matchAll/replaceAll must be called with a global RegExp" occurs when the String.prototype.matchAll() or String.prototype.replaceAll() method is used with a RegExp object that does not have the global flag set.

The JavaScript strict mode-only exception "setting getter-only property" occurs when there is an attempt to set a new value to a property for which only a getter is specified, or when setting a private accessor property that similarly only has a getter defined.