Javascript Cheat Sheet (Page 3 of 3) in pdf

Javascript Cheat Sheet Page 3

Arrays and Dictionaries

Here’s an example on how to use Array’s and Dictionaries

var

blah =

new

Array();

blah[0]="1";

//1 element

blah[1]="2";

//2 elements

blah[2]= 3;

//3 elements

blah.push(4.01);

// 4 elements

blah.push(function()

{console.log("i have

blahed");});

//5 elements

blah["Key"] = "Value";

//Not an element of the array

console.log(blah);

//prints ["1", "2", 3, 4.01, function()]

blah[4].call();

//Prints "i have blahed"

if(blah.length == 5) blah.pop();

console.log(blah.length);

//Prints 4

console.log(blah.toString());// Prints "1,2,3,4.01"

console.log(blah["Key"]);//Prints "Value"

As you can see, no types anywhere, Array contains a collection of different types, and everyone is

happy. It even includes an objection

! The objection here is an anonymous objection. They

(read function)

are essentially delegates. Things to note:



Array implements push and pop operations



All objects implement toString().



Element “Key” does not count to length. It can be used as a Dictionary ADT for KEY VALUE pairs.

(If this means nothing to you, forget it)



The anonymous objection can be called by using call(), since it doesn’t have its own name.

Javascript Cheat Sheet Page 3