JavaScript_Succinctly

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Make sure you understand that the head object is implied even when you don't explicitly include it, because the head object is the last stop in the scope chain. Notes Being explicit (e.g., window.alert() vs. alert()) costs a little bit more with regard to performance (how fast the code runs). It's faster if you rely on the scope chain alone and avoid explicitly referencing the head object even if you know the property you want is contained in the global scope. 82
Chapter 10 Object() Conceptual overview of using Object() objects Using the built-in Object() constructor function, we can create generic empty objects on the fly. In fact, if you remember back to the beginning of Chapter 1, this is exactly what we did by creating the cody object. Let’s recreate the cody object. Sample: sample69.html var cody = new Object(); // Create an empty object with no properties. for (key in cody) { // Confirm that cody is an empty generic object. if (cody.hasOwnProperty(key)) { console.log(key); // Should not see any logs, because cody itself has no properties. } } Here, all we are doing is using the Object() constructor function to create a generic object called cody. You can think of the Object() constructor as a cookie cutter for creating empty objects that have no predefined properties or methods (except, of course, those inherited from the prototype chain). Notes If it’s not obvious, the Object() constructor is an object itself. That is, the constructor function is based on an object created from the Function constructor. This can be confusing. Just remember that like the Array constructor, the Object constructor simply spits out blank objects. And yes, you can create all the empty objects you like. However, creating an empty object like cody is very different than creating your own constructor function with predefined properties. Make sure you understand that cody is just an empty object based on the Object() constructor. To really harness the power of <strong>JavaScript</strong>, you will need to learn not only how to create empty object containers from Object(), but also how to build your own "class" of objects (e.g., Person()) like the Object() constructor function itself. 83
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By Cody Lindley Foreword by Daniel
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Table of Contents About the Author
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Object() object instance properties
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The Story behind the Succinctly Ser
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About the Author Cody Lindley is a
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Advanced technical books written ab
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“Consider that the cody object cr
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Chapter 1 JavaScript Objects Creati
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Using JavaScript, the getGender met
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* The String() constructor function
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new object that is returned from th
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Notes The Math object is the oddbal
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In this snippet, we created a new s
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Verify that literals are created fr
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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
Page 62 and 63: console.log(stringObject); // Logs
Page 64 and 65: Chapter 4 Number() Conceptual overv
Page 66 and 67: NEGATIVE_INFINITY POSITIVE_INFINIT
Page 68 and 69: Parameter passed to Boolean() = Mat
Page 70 and 71: 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
Page 80 and 81: object. } // Logs bar, foo's value
Page 84 and 85: Object() parameters The Object() co
Page 86 and 87: Sample: sample72.html var cody = n
Page 88 and 89: Logs 'foo', being found at Object.p
Page 90 and 91: Sample: sample77.html var addFunct
Page 92 and 93: Sample: sample79.html var yelp = f
Page 94 and 95: parameters when defining the functi
Page 96 and 97: Notes The arguments.length property
Page 98 and 99: Invoking a function (function, meth
Page 100 and 101: Self-invoking anonymous function st
Page 102 and 103: the bar variable. All this is to sh
Page 104 and 105: Chapter 12 The this Keyword Concept
Page 106 and 107: Clearly, the value of this is based
Page 108 and 109: Working around the nested function
Page 110 and 111: What you need to learn here is that
Page 112 and 113: var john = new Person(); // No argu
Page 114 and 115: Notes An unlimited number of functi
Page 116 and 117: } (); How is the value of sayHiTex
Page 118 and 119: var parentFunction = function () {
Page 120 and 121: Chapter 14 Function Prototype Prope
Page 122 and 123: Sample: sample119.html var myFunct
Page 124 and 125: In this example, the foo property i
Page 126 and 127: console.log(FooInstance.constructor
Page 128 and 129: Providing a new object as the proto
Page 130 and 131: 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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