Table of Contents for

Effective JavaScript: 68 Specific Ways to Harness the Power of JavaScript

Index

Symbols

*, 10

~, 10

(, 25

!!, 151

==, 15–19

===, 17, 19

$, 169

%, 10

&, 10

&&, 13

+, 10, 12–14, 17, 25

++, 24–25

-, 10, 25

--, 24–25

., 28

<<, 10

>>, 10

>>>, 10

/, 25

;, 19–25

^, 10

|, 10

||, 13, 147, 151, 153

•, 185–186

, (expression sequencing operator), 55

[ ], 25, 107

A

Actors, 101

Actual argument, 67

add, 160–163

addChild, 96–97

addClass, 169

addEntry, 65

ai.js, 187–188

allKeys, 125–126

Anonymous function expressions, 41, 47–50, 60, 74

append, 66–67

apply, 65–67

Argument creep, 149

Arguments

options object, 149–153

order, 143–144

self-documenting, 149

and variadic functions, 67–72

arguments object, 3–5, 46, 67–72, 79–81, 138–140, 146, 148

Arithmetic operators, 7, 10

Array [[Class]], 107–109

Array constructor, 140–141

Array.isArray, 162

Array-like objects, 138–140, 160–164, 166

Array.prototype, 110–111

Arrays, 113–116, 123–125

associative, 114

concatenation, 139–140

every method, 137–138

filter method, 111, 135, 168

forEach method, 21, 72–73, 75, 108, 111, 128, 130–131, 134–138, 162, 191, 193–194

iteration, 132–138

literals, 140–141

map method, 61, 74–75, 98–100, 111, 134–135, 137, 139, 168

some method, 137–138

testing, 162–163

Asynchronous APIs, 171–175, 182

Asynchronous callbacks, 194–197

Asynchronous loops, 183–186

Automatic semicolon insertion, 19, 24

B

Backward compatibility, 3

Basic Multilingual Plane (BMP), 26–28

bind, 72–75, 177

Binding occurrence, 99–100

Bit vectors, 160, 165

Bitwise arithmetic operators, 7–8, 10

Block scoping, 42

Blocking APIs, 174–175

Blocking function, 172

Block-local functions, 50–52

Boolean [[Class]], 108–109

break, 24–25

buffer, 66–67, 72–74

Bullet symbol (•), 185–186

C

Cached files, 195–197

call, 63–65, 119–122, 138–140

Call stack, 184–186

Call stack inspection, 79–81

Callback function, 60, 62, 65, 72–73, 99–100, 175–179

Chainable API, 168–169

checkPassword, 84–86, 92–93, 95

choose, 199

[[Class]] internal property, 107–109

Classes, 86–87

Closures, 39–41, 75–77, 94–95, 176

Code point, 25–29

Code unit, 26–29

Coercion, 9–14, 18, 164–167

Comma-separated values (CSV), 98–100

Comments, 149

concat, 139–140

Concatenation, 3–5, 22–23, 139–140

Concurrency

asynchronous callbacks, 194–197

counter and data race, 190–194

error handling, 179–183

event queue, 172–175, 186–190

nested callbacks, 175–179

promises, 197–200

recursion, 183–186

const, 2

constructor, 140–141

Constructors, 57–59, 91

Context (graphics), 101

continue, 24–25

Countdown, 184–186

Counter and data race, 190–194

C.prototype, 83, 87

CSV (comma-separated values), 98–100

Curry, Haskell, 75

Currying, 75

D

Data race, 192, 198

Date [[Class]], 106, 108–109

Debugging, 48, 105, 182

decodeURI, 28

decodeURIcomponent, 28

Defensive programming, 165

Deferreds, 197

Diagnostic information, 105

Dict, 118–122, 130, 195–196

Dictionaries, 113–116, 123–125

Direct eval, 54–55

displayPage, 157–159

“Do what I mean” semantics, 17

Double negation pattern (!!), 151

Double-precision floating-point, 7–9

downloadAllAsync, 178–179, 181–182, 190–194

downloadAsync, 173–178, 180–184, 195

downloadCachingAsync, 195–196

downloadFiles, 177–178

downloadOneAsync, 183–186

downloadOneSync, 183

downloadSync, 172

downloadURL, 177

Dropped errors, 179–183

Duck testing, 161

Duck typing, 159

Duplicate code, 61, 180

Dynamic typing, 159

E

ECMAScript standard, 1–2, 19, 28, 55, 77, 106–108

Edition 5 (ES5), 1, 3, 134–135, 162

enable, 160–165

encodeURI, 28

encodeURIcomponent, 28

Enumerable properties, 125–127

Enumeration, 114–117, 123–132

Error [[Class]], 108–109

Error-handling callbacks, 180–181

Errors, 179–183

Escape sequences, 168

eval function, 52–55

Event loop, 173

Event queue, 171, 172–175, 186–190

Event-loop concurrency, 171

Eventual values, 198–200

every, 137–138

Exceptions, 44, 136, 179–180, 196–197

Expression sequencing operator (,), 55

extend function, 151–153

F

Falsy, 13–14

filter, 111, 135, 168

fillText, 154–155

Fixed-arity, 65, 67–68

Floating-point arithmetic, 124

Floating-point numbers, 7–9

Fluent style, 169

for loop, 24–25, 132–134

forEach, 21, 64–65, 72–73, 75, 108, 111, 128, 130–131, 134–138, 162, 191, 193–194

for...in loop, 113–116, 128–129, 132

Formal parameter, 67

Formatters, 157–159

Function [[Class]], 106, 108–109

Function declaration, 47

Function expression, 41, 47–50

Functions, 57–59

apply method, 65–67

arguments object, 3–5, 46, 67–72, 79–81, 138–140, 146, 148

bind method, 72–75, 177

call method, 63–65, 119–122, 138–140

call stack inspection, 79–81

closures, 75–77

higher-order, 60–63

toString method, 77–78

Futures, 197

G

Generic array methods, 138–140

getAuthor, 157–159

getCallStack, 79–80

getTitle, 157–159

Global variables, 31–34

guard, 165–167

H

hasOwnProperty, 64, 109, 115–122

Height/width, 143–144, 150

Higher-order functions, 60–63

highlight, 145–146

Hoisting, 42–44

hostname, 147

html method, 169

I

Identification number, 105–106

Image data, 102

Immediately invoked function expressions (IIFE), 5, 6, 44–46

Implementation inheritance, 83, 109

Implicit binding, 98–100

Implicit coercions, 9–14

Index, 138–139

Indirect eval, 54–55

Inheritance, 83–85, 89, 104, 108–109, 118, 158–159

ini object, 155–156

inNetwork, 189

Instance properties, 103

Instance state, 95–98

instanceof operator, 162

Integer addition, 125

Introspection, 109

isNaN, 11

isReallyNaN, 12

Iterator, 70–71

J

join, 198

jQuery, 169

JSON [[Class]], 108

JSON data format, 33

L

Last-in, first out, 185–186

length, 132–133, 138–139, 166

Lexical environment, 36–37

Lexical scope, 42, 122

Library, 143–144

Lightweight dictionaries, 113–116

line.split, 99–100

lint tools, 34–35

Literals, 140–141

Local variables, 34–35, 52–54

Logical OR operator (||), 147, 150–151

Lookup, 118–119

Loops, 183–186

M

map, 61, 74–75, 98–100, 111, 134–135, 137, 139, 168

Math [[Class]], 108

me, 100

MediaWiki, 157–158

Merging function, 151

Methods, 58–59

chaining, 167–170

storing on prototypes, 92–94

Mock object, 159

modal, 149–152

Module systems, 6

Monkey-patching, 110–111

moveTo, 102

N

Named function expression, 47

Naming conventions, 143–144

NaN (not a number), 11

Nested callbacks, 175–179

Nested function declaration, 52

Nested functions, 71–72

new, 59, 83, 89–91

newline, 19, 24–25

next, 189

Node.js, 181

NodeList, 138–140

Nonblocking APIs, 172

Nondeterminism, 130–132, 192

Nonstandard features, 2–3

null, 146

Number [[Class]], 108

O

Object [[Class]], 108

Object extension function, 151–153

Object introspection, 109

Objects as scopes, 49

Object wrappers, 15–16

Object.create, 89–91, 103–105, 116–117

Object.defineProperty, 126–127

Object.getPrototypeOf, 83–88, 109

Object.prototype, 115–116, 118–122, 125–127

Objects, 127–132, 138–140

hasOwnProperty method, 64, 109, 115–122

toString method, 12–14, 17–18, 107, 163

Operators

arithmetic, 7, 10, 21

bitwise, 8–9, 166

bitwise arithmetic, 10

expression sequencing (,), 55

typeof, 7, 14, 165–166

Optional arguments, 149–150

Options object, 149–153

or, 166–167

Order dependencies, 123–125

Overloading structural types, 161

P

Page class, 158–159

pick, 130–131

Pollution of objects, 87

Polyfill, 111

Positional arguments, 149–150

postMessage, 187–189

Predicates, 135, 137

Primitives, 15–18

Private data, 94–95, 106

Profiling, 105

Promises, 197–200

Property descriptor map, 116–117

Property names, 105–106

__proto__, 83–84, 86–89, 109, 117, 121

Prototype pollution, 115–122

Prototypes

C.prototype, 83, 87

as implementation detail, 109–110

instance state, 95–98

Object.getPrototypeOf, 83–88

__proto__, 83–84, 86–89, 109, 117, 121

storing methods on, 92–94

Q

Querying web pages, 169

R

Radix, 8

Receiver, 58–59, 63–65, 72–73

Recursion, 183–186

RegExp, 108–109

removeClass, 169

replace, 167–168

Restricted productions, 24

return, 24–25, 91

Run-to-completion guarantee, 172, 175

S

Scene graph, 101

Scope, 31

anonymous and named function expressions, 47–50

block-local functions, 50–52

closures, 39–41

eval function, 52–55

global variables, 31–34

hoisting, 42–44

immediately invoked function expressions (IIFE), 5, 6, 44–46

local variables, 34–35

with statement, 35–39

Scope chain, 36

Security, 79, 94–95

select, 199–200

self, 90–91, 100, 167

Self-documenting arguments, 149

Semicolon, 19–25

setSection, 155–156

setTimeout, 189–191, 196

shift, 68–69

Shift operators, 10

Short-circuiting methods, 137

Single character pattern, 28

slice, 70, 140

some, 137–138

sort, 60

Source object, 151–153

split, 110

Stack inspection, 79–81

Stack overflow, 185

Stack trace, 79–81

State

instance state, 95–98

stateful API, 154–155, 169

stateless API, 153–156, 167–169

Strict equality, 17–18

Strict mode, 3–6, 51, 69–70

String, 15–16

String characters, replacing, 167–169

String [[Class]], 108–109

String literal, 3

String sets, 160–163

Strings, 75–76

Structural types, 161

Structural typing, 159

Subclass constructors, 101–105

Superclass constructors, 101–105

Superclass property names, 105–106

Supplementary plane, 27

Surrogate pair, 27–29

Synchronous function, 172

T

takeWhile, 135–137

Target object, 151–153

Termination, 133–134

Text formatting, 156, 159

that, 100

then, 197–199

32-bit integers, 7, 10

this, 58–59, 66, 98–100, 169

Threads, 172

throw, 24–25

toHTML, 157–159

Tokens, 20–22, 25

toString, 7–8, 12–14, 17–18, 77–78, 84–86, 92–95, 153, 167

trimSections, 42–43

true, 146

Truthiness, 13, 147–149

Truthy, 13, 135, 137, 147

try, 179, 182

tryNextURL, 183–184

Type errors, 9, 12

TypeError, 90, 108

typeof, 7, 14, 165–166

U

UCS-2, 26–27

uint32, 166

Unary operator, 17

undefined, 11, 14, 144–151, 169

Underscore character, 94

Unicode, 25–29

use strict, 3–6

User class, 86

User.prototype, 84–87, 90–91, 93

UTF-8, 26

UTF-16, 26–28

UTF-32, 26

V

val, 41

valueOf, 12–14, 16–18

var, 22, 32–35, 42–53

Variable hoisting, 42–44

Variable-arity function, 65–66, 68

Variable-length encoding, 27

Variadic function, 65–66, 68

W

Web development practices, 144

when, 198

while loop, 130–132, 188–189

Width/height, 143–144, 150

Wiki formatter, 157

Wiki library, 156–160

with statement, 35–39

Worker, 187–188

Work-list, 131

Work-set, 127–131

wrapElements, 44–46

X

x and y, 38, 104, 150, 152

XMLHttpRequest library, 174–175