JavaScript data types and data structures
JavaScript data types and data structures
Programming languages all have built-in data structures, but these often differ from one language to another.
This article attempts to list the built-in data structures available in JavaScript and what properties they have;these can be used to build other data structures.
Wherever possible, comparisons with other languages are drawn.
Dynamic typing
JavaScript is a loosely typed or a dynamic language.
Variables in JavaScript are not directly associated with any particular value type, and any variable can be assigned (and re-assigned) values of all types:
var foo = 42; // foo is now a number foo = 'bar'; // foo is now a string foo = true; // foo is now a boolean
Data types
The latest ECMAScript standard defines eight data types: