JavaScript: The Language

Fundamental JavaScript: The Language Presented by Brian Dukes

Where are we going?
Feature Overview
Syntax
Objects
Functions
Inheritance
Miscellaneous

Feature Overview
1st Class Functions
Loose Typing
Dynamic Objects
Prototypal Inheritance
Global Variables

Where are we?
Feature Overview
Syntax
Objects
Functions
Inheritance
Miscellaneous

Syntax: Primitive Types
Number
64-bit floating, " double "
String
Surrounded by single or double quotes
Boolean
true or false
Objects
Key/value pairs
Arrays
Indexed collection
Functions
Callable code

Syntax: Truthy & Falsy Values
Falsy values:
false
null
undefined
''
0
NaN
Truthy values:
Everything else
true , 'false' , {}

Syntax: Statements & Operators
var
if
switch
while
for
for in
do while
try
throw
return
break
with
ternary ( ? : )
typeof
||
&&
== & ===
!= & !==
+
!

Where are we?
Feature Overview
Syntax
Objects
Functions
Inheritance
Miscellaneous

Objects: Literals
JSON (plus functions)
Name/value pairs
Name is any string
Quotes are optional for legal name
Value can be any JavaScript value:
Other objects
Functions
Arrays

Objects: Setting & Getting
var flight = {
airline: "Oceanic",
number: 815
};
alert(flight.airline);
alert(flight.equipment); // undefined
flight.equipment.status // throw "TypeError"
flight.equipment = {
model: 'Boeing 777'
};
flight['flight-status'] = 'overdue';
alert(flight["flight-status"]);

Where are we?
Feature Overview
Syntax
Objects
Functions
Inheritance
Miscellaneous

Functions: Definition
Functions are objects
Functions have a prototype
Functions can have properties
Functions can have methods
Functions can be passed as arguments to functions
Functions can be returned from functions
Functions can be invoked

Functions: Closure
Functions have access to outer variables
this & arguments are different for each function
var i;
for (i = 0; i < 10; i++) {
setTimeout(function () {
console.log(i*i);
}, i);
}

Functions: Scope
Does not have block scope
Unlike every other language with C style syntax
Function scope
function outer () {
for (var i = 0; i < 10; i++) {
var double = i+i;
$link.click(function () {
alert(double)
});
}
}

Functions: Callbacks
Functions can be passed to other functions

makeAjaxCall(function (result) {
alert(result);
});

Functions: Module Pattern
Call an anonymous function after declaring it ( IIFE )
Keeps inner values from being accessible outside of the function

(function () {
var x = 1;
}());

Where are we?
Feature Overview
Syntax
Objects
Functions
Inheritance
Miscellaneous

Inheritance: Pseudoclassical
new operator
Function names are capitalized, by convention
Lots of downfalls

Inheritance: Prototype
All objects has a prototype property
When retrieving properties, any property not on the object is retrieved from its prototype
If the property isn't on the prototype, its prototype is checked, etc.

Where are we?
Feature Overview
Syntax
Objects
Functions
Inheritance
Miscellaneous

Miscellaneous: Arrays
Literal notation: [true, 1, "string", {}]
length property
Not bounded
Use push method to add to the end
Is a weird object, not a "real" array

Miscellaneous: Regular Expressions
Pattern Matching
Literal notation: /pattern/options

Resources
JavaScript Weekly - http://javascriptweekly.com/
JSLint - http://www.jslint.com/
JSLint.VS2010 - http://bit.ly/JSLint-VS2010
jsFiddle - http://jsfiddle.net/
MDC - https://developer.mozilla.org
This - http://www.slideshare.net/EngageSoftware/

JavaScript: The Language

by Engage Software on May 24, 2011

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