Posts Tagged ‘literal notation’

Using literals

Monday, September 14th, 2009

Array literals

In JavaScript you can define an array like this:

var a = new Array();

A better pattern to do so is by using the array literal, basically a comma-delimited list of values, wrapped in square brackets:

var a = []; // array with no elements
var a = [1, 2, 3]; // array with three elements
var a = [[1, 2, 3], ['a', 'b', 'c']]; // array of two arrays

Object literals

Similarly, an empty object can be defined as:

var o = new Object();

A much better pattern is to use the object literal:

var o = {}; // empty object
var o = {p: 'one'}; // object with a "p" property
var o = { 
  prop: 1,  // a property
  meth: function() { // a method

Literal Notations

Saturday, May 17th, 2008

A little something from my forthcoming book "Object-Oriented JavaScript" I thought would be nice to share.

Literal Notations
name literal constructor example
object {} new Object() {prop: 1}
array [] new Array() [1,2,3,'test']
regular expression
/pattern/modifiers new RegExp('pattern', 'modifiers') /java.*/img