Object.defineProperty() method defines a new property directly on an object, or modifies an existing property on an object, and returns the object.
Object.isExtensible() method determines if an object is extensible (whether it can have new properties added to it).
Object.isFrozen() determines if an object is frozen.
Object.isSealed() method determines if an object is sealed.
method returns an array of a given object's own enumerable properties, in the same order as that provided by a
loop (the difference being that a for-in loop enumerates properties in the prototype chain as well).
Object.preventExtensions() method prevents new properties from ever being added to an object (i.e. prevents future extensions to the object).
Object.seal() method seals an object, preventing new properties from being added to it and marking all existing properties as non-configurable. Values of present properties can still be changed as long as they are writable.
Object.getOwnPropertyNames() method returns an array of all properties (enumerable or not) found directly upon a given object.
object is used to represent a generic, fixed-length raw binary data buffer. You cannot directly manipulate the contents of an
; instead, you create one of the typed array objects
object which represents the buffer in a specific format, and use that to read and write the contents of the buffer.
Boolean object is an object wrapper for a boolean value.
typed array represents an array of 32-bit floating point numbers (corresponding to the C
data type) in the platform byte order. If control over byte order is needed, use
instead. The contents are initialized to
. 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).
Promise object is used for asynchronous computations. A
Promise represents a value which may be available now, or in the future, or never.
(often shortened to JS
) is a lightweight, interpreted, object-oriented language with first-class functions
, and is best known as the scripting language for Web pages, but it's used in many non-browser environments
as well. It is a prototype-based
, multi-paradigm scripting language that is dynamic, and supports object-oriented, imperative, and functional programming styles.
Closures are functions that refer to independent (free) variables (variables that are used locally, but defined in an enclosing scope). In other words, these functions 'remember' the environment in which they were created.