JavaScript

JavaScript is a high level interpreted language.

Data types

The latest ECMAScript standard defines eight data types.

Primitives

All types except objects define immutable values.

Type
Boolean Logical entity having a true or false value
Number Double-precision 64-bit binary format IEEE 754 value
BigInt Represent integers with arbitrary precision and beyond the safe integer limit
String Set of unsigned 16-bit integer values used for textual representations
Symbol Unique value used as the key of an Object property
Null null value
Undefined undefined value

Objects

In computer science, an object is a value in memory which is possibly referenced by an identifier.

Properties

In JavaScript, objects can be seen as a collection of properties. Properties are identified using key values. A key value is either a String value or a Symbol value. Property values can be values of any type which enables building complex data structures.

"Normal" objects, and functions

A JavaScript object is a mapping between keys and values. Keys are strings or Symbols, and values can be anything.

Functions are regular objects with the additional capability of being callable.

Indexed collections

  • Array

Keyed collections

  • Map
  • Set
  • WeakMap
  • WeakSet

Structured data

  • JSON

TODO: Expound

js drafts

Resources