JavaScript_Succinctly

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Table of Contents About the Author ......................................................................................................... 10 Introduction ................................................................................................................. 11 Preface ......................................................................................................................... 13 More code, less words ............................................................................................... 13 Exhaustive code and repetition .................................................................................. 13 Color-coding conventions .......................................................................................... 13 Code examples .......................................................................................................... 14 Chapter 1: JavaScript Objects ................................................................................... 16 Creating objects ......................................................................................................... 16 JavaScript constructors create and return object instances ....................................... 21 The native JavaScript object constructors ................................................................. 23 User-defined/non-native object constructor functions ................................................ 24 Instantiating constructors using the new operator ...................................................... 25 Creating shorthand or literal values from constructors ............................................... 27 Primitive (aka simple) values ..................................................................................... 28 The primitive values null, undefined, "string", 10, true, and false are not objects ....................................................................................................................... 30 How primitive values are stored/copied in JavaScript ................................................ 31 Primitive values are equal by value ........................................................................... 32 The string, number, and Boolean primitive values act like objects when used like objects ....................................................................................................................... 33 Complex (aka composite) values ............................................................................... 34 How complex values are stored/copied in JavaScript ................................................ 35 Complex objects are equal by reference ................................................................... 36 Complex objects have dynamic properties ................................................................ 37 The typeof operator used on primitive and complex values ..................................... 37 Dynamic properties allow for mutable objects ........................................................... 39 All constructor instances have constructor properties that point to their constructor function ...................................................................................................................... 40 Verify that an object is an instance of a particular constructor function ..................... 42 An instance created from a constructor can have its own independent properties (aka instance properties) ................................................................................................... 43 The semantics of "JavaScript objects" and "Object() objects" ................................ 44 Chapter 2: Working with Objects and Properties ..................................................... 46 Complex objects can contain most of the JavaScript values as properties ................ 46 Encapsulating complex objects in a programmatically beneficial way ....................... 47 Getting, setting, and updating an object's properties using dot notation or bracket notation ...................................................................................................................... 48 4
5 Deleting object properties .......................................................................................... 51 How references to object properties are resolved ..................................................... 51 Using hasOwnProperty to verify that an object property is not from the prototype chain .......................................................................................................................... 54 Checking if an object contains a given property using the in operator ...................... 55 Enumerate (loop over) an object’s properties using the for in loop ........................ 55 Host objects and native objects ................................................................................. 56 Enhancing and extending objects with Underscore.js ............................................... 58 Chapter 3: String() .................................................................................................... 61 Conceptual overview of using the String() object ................................................... 61 String() parameters ................................................................................................ 61 String() properties and methods ............................................................................ 62 String object instance properties and methods .......................................................... 62 Chapter 4: Number() .................................................................................................... 64 Conceptual overview of using the Number() object ................................................... 64 Integers and floating-point numbers .......................................................................... 64 Number() parameters ................................................................................................ 65 Number() properties .................................................................................................. 65 Number object instance properties and methods ...................................................... 66 Chapter 5: Boolean() .................................................................................................. 67 Conceptual overview of using the Boolean() object ................................................. 67 Boolean() parameters .............................................................................................. 67 Boolean() properties and methods .......................................................................... 68 Boolean object instance properties and methods ...................................................... 68 Non-primitive false Boolean objects convert to true ................................................... 68 Certain things are false, everything else is true ......................................................... 69 Chapter 6: Working with Primitive String, Number, and Boolean Values .............. 71 Primitive/literal values are converted to objects when properties are accessed ........ 71 You should typically use primitive string, number, and Boolean values ..................... 72 Chapter 7: Null ............................................................................................................. 74 Conceptual overview of using the null value............................................................ 74 typeof returns null values as "object" ..................................................................... 74 Chapter 8: Undefined .................................................................................................. 76 Conceptual overview of the undefined value ........................................................... 76 JavaScript ECMA-262 Edition 3 (and later) declares the undefined variable in the global scope .............................................................................................................. 76 Chapter 9: The Head/Global Object ........................................................................... 78 Conceptual overview of the head object .................................................................... 78 Global functions contained within the head object ..................................................... 79 The head object vs. global properties and global variables ....................................... 79 Referring to the head object ...................................................................................... 80 The head object is implied and typically not referenced explicitly .............................. 81 Chapter 10: Object() .................................................................................................. 83 Conceptual overview of using Object() objects ....................................................... 83 Object() parameters ................................................................................................ 84 Object() properties and methods ............................................................................ 85
Page 2 and 3: By Cody Lindley Foreword by Daniel
Page 6 and 7: Object() object instance properties
Page 8 and 9: The Story behind the Succinctly Ser
Page 10 and 11: About the Author Cody Lindley is a
Page 12 and 13: Advanced technical books written ab
Page 14 and 15: “Consider that the cody object cr
Page 16 and 17: Chapter 1 JavaScript Objects Creati
Page 18 and 19: Using JavaScript, the getGender met
Page 20 and 21: * The String() constructor function
Page 22 and 23: new object that is returned from th
Page 24 and 25: Notes The Math object is the oddbal
Page 26 and 27: In this snippet, we created a new s
Page 28 and 29: Verify that literals are created fr
Page 30 and 31: The primitive values null, undefine
Page 32 and 33: The concept to take away here is th
Page 34 and 35: * This will throw an error and not
Page 36 and 37: copied, but not the actual value. T
Page 38 and 39: Sample: sample21.html // Primitive
Page 40 and 41: Notes Careful! If you mutate the na
Page 42 and 43: console.log(instanceOfCustomObject.
Page 44 and 45: myObject.prop = 'test'; myArray.pro
Page 46 and 47: Chapter 2 Working with Objects and
Page 48 and 49: Sample: sample31.html // Encapsula
Page 50 and 51: cody['getGender']() // Just slap th
Page 52 and 53: een defined. You might think that b
Page 54 and 55:
console.log(myArray.toLocaleString(
Page 56 and 57:
Sample: sample44.html var cody = {
Page 58 and 59:
Sometimes a web browser manufacture
Page 60 and 61:
I like this library because it take
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console.log(stringObject); // Logs
Page 64 and 65:
Chapter 4 Number() Conceptual overv
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NEGATIVE_INFINITY POSITIVE_INFINIT
Page 68 and 69:
Parameter passed to Boolean() = Mat
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console.log(Boolean(Math)); console
Page 72 and 73:
var numberObject = new Number(1.100
Page 74 and 75:
Chapter 7 Null Conceptual overview
Page 76 and 77:
Chapter 8 Undefined Conceptual over
Page 78 and 79:
Chapter 9 The Head/Global Object Co
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object. } // Logs bar, foo's value
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Make sure you understand that the h
Page 84 and 85:
Object() parameters The Object() co
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Sample: sample72.html var cody = n
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Logs 'foo', being found at Object.p
Page 90 and 91:
Sample: sample77.html var addFunct
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Sample: sample79.html var yelp = f
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parameters when defining the functi
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Notes The arguments.length property
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Invoking a function (function, meth
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Self-invoking anonymous function st
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the bar variable. All this is to sh
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Chapter 12 The this Keyword Concept
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Clearly, the value of this is based
Page 108 and 109:
Working around the nested function
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What you need to learn here is that
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var john = new Person(); // No argu
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Notes An unlimited number of functi
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} (); How is the value of sayHiTex
Page 118 and 119:
var parentFunction = function () {
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Chapter 14 Function Prototype Prope
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Sample: sample119.html var myFunct
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In this example, the foo property i
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console.log(FooInstance.constructor
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Providing a new object as the proto
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var chuck = new Person(0, 0); conso
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An Array() is just a special type o
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It is more common to see an array d
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console.log(myArray.length); // Log
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while (myArrayLength--) { // If len
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ceil() cos() exp() floor() log() ma
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That is: a complex value is equal t
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JavaScript_Succinctly

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