JavaScript Notes for Professionals - goalkicker.com

1 JavaScriptNotes for ProfessionalsJavaScript Notes for Programming BooksDisclaimerThis is an uno cial free book created for educational purposes and isnot a liated with o cial JavaScript group(s) or company(s).All trademarks and registered trademarks arethe property of their respective owners400+ pagesof professional hints and tricksContentsAbout 1 .. Chapter 1: Getting started with JavaScript 2 .. Section : Using () 2 .. Section : Using the DOM API 4 .. Section : Using () 5 .. Section : Using () 6 .. Section : Using () 7 .. Section : Using the DOM API (with graphical text: Canvas, SVG, or image file) 8 .. Chapter 2: JavaScript Variables 10 .. Section : Defining a Variable 10 .. Section : Using a Variable 10 .. Section : Types of Variables 10.

2 Section : Arrays and Objects 11 .. Chapter 3: Built-in Constants 12 .. Section : null 12 .. Section : Testing for NaN using isNaN() 12 .. Section : NaN 13 .. Section : undefined and null 14 .. Section : Infinity and -Infinity 15 .. Section : Number constants 15 .. Section : Operations that return NaN 16 .. Section : Math library functions that return NaN 16 .. Chapter 4: Comments 17 .. Section : Using Comments 17 .. Section : Using HTML comments in JavaScript (Bad practice) 17 .. Chapter 5: Console 19 .. Section : Measuring time - () 22 .. Section : Formatting console output 23 .. Section : Printing to a browser's debugging console 24 .. Section : Including a stack trace when logging - () 26 .. Section : Tabulating values - () 26 .. Section : Counting - () 28.

3 Section : Clearing the console - () 30 .. Section : Displaying objects and XML interactively - (), () 30 .. Section : Debugging with assertions - () 32 .. Chapter 6: Datatypes in JavaScript 33 .. Section : typeof 33 .. Section : Finding an object's class 34 .. Section : Getting object type by constructor name 34 .. Chapter 7: Strings 37 .. Section : Basic Info and String Concatenation 37 .. Section : Reverse String 38 .. Section : Comparing Strings Lexicographically 39 .. Section : Access character at index in string 40 .. Section : Escaping quotes 40 .. Section : Word Counter 41 .. Section : Trim whitespace 41 .. Section : Splitting a string into an array 41 .. Section : Strings are unicode 42 .. Section : Detecting a string 42 .. Section : Substrings with slice 43.

4 Section : Character code 43 .. Section : String Representations of Numbers 43 .. Section : String Find and Replace Functions 44 .. Section : Find the index of a substring inside a string 45 .. Section : String to Upper Case 45 .. Section : String to Lower Case 46 .. Section : Repeat a String 46 .. Chapter 8: Date 47 .. Section : Create a new Date object 47 .. Section : Convert to a string format 49 .. Section : Creating a Date from UTC 50 .. Section : Formatting a JavaScript date 53 .. Section : Get the number of milliseconds elapsed since 1 January 1970 00:00:00 UTC 55 .. Section : Get the current time and date 55 .. Section : Increment a Date Object 56 .. Section : Convert to JSON 57 .. Chapter 9: Date Comparison 58 .. Section : Comparing Date values 58.

5 Section : Date Di erence Calculation 59 .. Chapter 10: Comparison Operations 60 .. Section : Abstract equality / inequality and type conversion 60 .. Section : NaN Property of the Global Object 61 .. Section : Short-circuiting in boolean operators 63 .. Section : Null and Undefined 65 .. Section : Abstract Equality (==) 65 .. Section : Logic Operators with Booleans 66 .. Section : Automatic Type Conversions 67 .. Section : Logic Operators with Non-boolean values (boolean coercion) 67 .. Section : Empty Array 68 .. Section : Equality comparison operations 68 .. Section : Relational operators (<, <=, >, >=) 70 .. Section : Inequality 71 .. Section : List of Comparison Operators 72 .. Section : Grouping multiple logic statements 72 .. Section : Bit fields to optimise comparison of multi state data 72.

6 Chapter 11: Conditions 74 .. Section : Ternary operators 74 .. Section : Switch statement 75 .. Section : If / Else If / Else Control 77 .. Section : Strategy 78 .. Section : Using || and && short circuiting 79 .. Chapter 12: Arrays 80 .. Section : Converting Array-like Objects to Arrays 80 .. Section : Reducing values 82 .. Section : Mapping values 84 .. Section : Filtering Object Arrays 84 .. Section : Sorting Arrays 86 .. Section : Iteration 88 .. Section : Destructuring an array 92 .. Section : Removing duplicate elements 93 .. Section : Array comparison 93 .. Section : Reversing arrays 94 .. Section : Shallow cloning an array 95 .. Section : Concatenating Arrays 95 .. Section : Merge two array as key value pair 97 .. Section : Array spread / rest 97.

7 Section : Filtering values 98 .. Section : Searching an Array 99 .. Section : Convert a String to an Array 100 .. Section : Removing items from an array 100 .. Section : Removing all elements 101 .. Section : Finding the minimum or maximum element 102 .. Section : Standard array initialization 103 .. Section : Joining array elements in a string 104 .. Section : Removing/Adding elements using splice() 105 .. Section : The entries() method 105 .. Section : Remove value from array 105 .. Section : Flattening Arrays 106 .. Section : Append / Prepend items to Array 107 .. Section : Object keys and values to array 107 .. Section : Logical connective of values 108 .. Section : Checking if an object is an Array 108 .. Section : Insert an item into an array at a specific index 109.

8 Section : Sorting multidimensional array 109 .. Section : Test all array items for equality 110 .. Section : Copy part of an Array 110 .. Chapter 13: Objects 112 .. Section : Shallow cloning 112 .. Section : 112 .. Section : Object cloning 113 .. Section : Object properties iteration 114 .. Section : 115 .. Section : Object rest/spread (..) 116 .. Section : 116 .. Section : Accesor properties (get and set) 117 .. Section : Dynamic / variable property names 117 .. Section : Arrays are Objects 118 .. Section : 119 .. Section : Convert object's values to array 120 .. Section : Retrieving properties from an object 120 .. Section : Read-Only property 123 .. Section : Non enumerable property 123 .. Section : Lock property description 123.

9 Section : 124 .. Section : Descriptors and Named Properties 124 .. Section : 126 .. Section : Properties with special characters or reserved words 126 .. Section : Creating an Iterable object 127 .. Section : Iterating over Object entries - () 127 .. Section : () 128 .. Chapter 14: Arithmetic (Math) 129 .. Section : Constants 129 .. Section : Remainder / Modulus (%) 129 .. Section : Rounding 130 .. Section : Trigonometry 132 .. Section : Bitwise operators 133 .. Section : Incrementing (++) 135 .. Section : Exponentiation ( () or **) 135 .. Section : Random Integers and Floats 136 .. Section : Addition (+) 137 .. Section : Little / Big endian for typed arrays when using bitwise operators 137 .. Section : Get Random Between Two Numbers 138.

10 Section : Simulating events with di erent probabilities 139 .. Section : Subtraction (-) 140 .. Section : Multiplication (*) 140 .. Section : Getting maximum and minimum 140 .. Section : Restrict Number to Min/Max Range 141 .. Section : Ceiling and Floor 141 .. Section : Getting roots of a number 142 .. Section : Random with gaussian distribution 142 .. Section : to find direction 143 .. Section : Sin & Cos to create a vector given direction & distance 143 .. Section : 144 .. Section : Periodic functions using 145 .. Section : Division (/) 146 .. Section : Decrementing (--) 146 .. Chapter 15: Bitwise operators 148 .. Section : Bitwise operators 148 .. Section : Shift Operators 150 .. Chapter 16: Constructor functions 151 .. Section : Declaring a constructor function 151.