javascript mini books

7/30/2019 javascript mini books

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JavaScriptEloquent JavaScript: A Modern Introduction to Programming

Marijn Haverbeke


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JavaScript JavaScript

JavaScript JavaScript JavaScript

JavaScript

12 1~3 JavaScript JavaScript

4~7 JavaScript JavaScript

8~12 JavaScript

Web HTTP

Copyright 2011 by Marijn Haverbeke. Title of English-language original: Eloquent JavaScript, ISBN 978-1-

59327-282-1, published by No Starch Press.

Simplified Chinese-language edition copyright 2012 by China Machine Press.

No part of this book may be reproduced or transmitted in any form or by any means, elec tronic or mechanical,

including photocopying, recording or any information storage and retrieval system, without permission, in writing,

from the publisher.

All rights reserved. No Starch Press

01-2012-2098

CIP

JavaScript / Haverbeke M. . 2012.9

Eloquent JavaScript: A Modern Introduction to Programming

ISBN 978-7-111-39665-9

. J . . JAVA - . TP312

CIP 2012 210644

22 100037

2012 10 1 1

186mm

240mm

11ISBN 978-7-111-39665-9

49.00

010 88378991 88361066010 68326294 88379649 68995259010 88379604

[email protected]


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JavaScript Brendan Eich JavaScript

Angus Croll Twitter

JavaScript Marijn Haverbeke Joey deVilla Global Nerdy


JavaScript Chris Williams JSConf

JavaScript Rey Bango Client-Web jQuery

JavaScript Ben Nadel Epicenter

Design Shack

JavaScript Designorati

JavaScript Craig Buckler OptimalWorks Web Design


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JavaScript

Ajax

JavaScript

JavaScript

JavaScript

JavaScript

http://www.cnblogs.com/TomXu

[email protected]


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20 70 BASIC

20 70

BASIC JavaScript Web

JavaScript

Donald Knuth

Joseph Weizenbaum Computer Power and Human Reason


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VI

00110001 00000000 0000000000110001 00000001 0000000100110011 00000001 00000010

01010001 00001011 0000001000100010 00000010 0000100001000011 00000001 0000000001000001 00000001 0000000100010000 00000010 0000000001100010 00000000 00000000

I

1 10 1 + 2 + + 10 = 55

1 0

1 0 0

2 1 1

3 1 2


8/61

VII

4 2 11

5 2 0 9

6 1 0

7 1 18 3

9 0

Set 'total' to 0Set 'count' to 1

[loop]Set 'compare' to 'count'Subtract 11 from 'compare'

If 'compare' is zero, continue at [end]Add 'count' to 'total'Add 1 to 'count'Continue at [loop]

[end]Output 'total'

I

total

count compare

count 11

compare

count 11 count total

count 11 count 1

JavaScript

var total = 0, count = 1;while (count


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VIII

print 1 10

range sum sum range

while

sum range

JavaScript

JavaScript

node.js JavaScript

JavaScript

JavaScript

JavaScript

JavaScript

JavaScript


JavaScript Java

1995 JavaScript Java

Java

JavaScript ECMAScript JavaScript

ECMAScript ECMA

ECMAScript Web

JavaScript ECMAScript 3

JavaScript ECMAScript 3

print(sum(range(1, 10)));

I


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IX

http://eloquentjavascript.net/

HTML

test.html

var total = 0, count = 1;while (count


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1 + 1

2

I

http://nostarch.com/ejs.htm

X


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1 JavaScript

1

1.1 1

1.1.1 1

1.1.2 2

1.1.3 3

1.1.4 3

1.1.5 4

1.1.6 5

1.2 5

1.3 7

1.3.1 7

1.3.2 prompt confirm 7

1.3.3 print 8

1.3.4 8

1.4 8

1.4.1 9

1.4.2 while do 9

1.4.3 11

1.4.4 for 11

1.4.5 12

1.4.6 12

1.4.7 switch 12

1.4.8 13

1.4.9 13

1.5 14

1.5.1 Undefined 14

1.5.2 14

1.5.3 15

1.5.4 && || 16

2 17

2.1 17

2.1.1 18

2.1.2 18

2.1.3 19

2.1.4 20

2.1.5 20

2.1.6 212.1.7 21

2.2 22

2.2.1 22

2.2.2 23

2.2.3 24

3 27

3.1 Emily 27

3.2 283.2.1 28

3.2.2 29

3.2.3 30

3.2.4 30

3.2.5 31


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XII

3.2.6 32

3.3 Emily 33

3.3.1 33

3.3.2 34

3.3.3 35

3.3.4 35

3.3.5 36

3.3.6 38

3.3.7 39

3.3.8 40

3.3.9 41

3.4 42

3.4.1 arguments 42

3.4.2 44

3.4.3 Math 44

3.4.4 44

4 47

4.1 47

4.1.1 47

4.1.2 48

4.2 48

4.2.1 48

4.2.2 49

4.2.3 50

4.2.4 Error 51

4.2.5 51

4.2.6 Catch 51

4.3 52

5 55

5.1 55

5.2 56

5.2.1 57

5.2.2 58

5.2.3 59

5.3 59

5.3.1 HTML 60

5.3.2 61

5.3.3 64

5.3.4 64

5.3.5 67

5.3.6 HTML 67

5.3.7 70

5.4 71

5.4.1 71

5.4.2 72

5.4.3 73

6 75

6.1 75

6.1.1 75

6.1.2 76

6.1.3 77

6.1.4 77

6.1.5 79

6.1.6 80

6.1.7 81

6.2 82

6.2.1 82

6.2.2 83

6.2.3 83

6.2.4 85

6.2.5 86

6.2.6 this 87

6.2.7 88

6.2.8 90

6.2.9 90

6.2.10 93


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XIII

6.3 93

6.3.1 93

6.3.2 94

6.3.3 96

6.3.4 97

6.3.5 97

6.3.6 99

6.4 100

6.4.1 100

6.4.2 101

6.4.3 102

6.4.4 instanceof 103

6.4.5 104

7 107

7.1 107

7.1.1 107

7.1.2 108

7.2 108

7.2.1 109

7.2.2 110

7.3 111

7.3.1 111

7.3.2 111

7.3.3 112

7.3.4 112

7.4 JS 113

8 115

8.1 115

8.1.1 115

8.1.2 116

8.1.3 117

8.1.4 117

8.1.5 117

8.2 118

8.2.1 118

8.2.2 118

8.2.3 RegExp 120

8.3 .ini 121

8.4 123

9 Web 125

9.1 125

9.1.1 URL 125

9.1.2 126

9.1.3 126

9.2 Web 126

9.2.1 windows 126

9.2.2 document 127

9.2.3 128

9.2.4 128

9.2.5 130

9.2.6 132

9.3 132

9.4 133

10 135

10.1 DOM 135

10.1.1 136

10.1.2 136

10.1.3 innerHTML 137

10.1.4 137

10.1.5 138

10.1.6 138

10.1.7 139

10.1.8 print 140

10.2 140

10.2.1 141

10.2.2 141


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XIV

10.2.3 141

10.2.4 142

10.3 142

11 143

11.1 143

11.1.1 143

11.1.2 145

11.1.3 145

11.1.4 146

11.1.5 147

11.1.6 147

11.1.7 148

11.1.8 148

11.1.9 window 149

11.2 149

11.2.1 149

11.2.2 150

11.2.3 150

11.2.4 153

12 HTTP 157

12.1 HTTP 157

12.2 XMLHttpRequest API 158

12.2.1 158

12.2.2 158

12.2.3 159

12.2.4 XML 160

12.2.5 JSON 161

12.2.6 161

12.3 HTTP 162


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1

JavaScript

bit

bit 0 1

1.1

JavaScript

JavaScript 6

number string Boolean object function undefined

bit

1.1.1

number

144

144 144 bit 144

0100000001100010000000000000000000000000000000000000000000000000

10010000 144

JavaScript 64

bit 64 1 0


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2 1

264 10 19

JavaScript 10 19

bit 11

bit52 bit 252 10 15 JavaScript

.

9.81

e e

2.998e8

2.998

108

=299800000integer 52 bit

p 64 bit

1.1.2

JavaScript

100 + 4 * 11

+ *

4 100 11

(100 + 4) * 11

- /

1- 2 + 1

% X%Y X Y 314 %

100 14 10 % 3 1 144 % 12 0 %

53 bit bit IEEE 754


18/61


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4 1

typeof -

- (10 - 2) -8

l l l l

1.1.5

true false3 > 2 true3 < 2 false

l l l l

>


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5 JavaScript

! false true

| |

&& > ==

1.1.6

JavaScript 22 psychoanalysis

JavaScript

;

1;!false;

side

effect 1 true bit

JavaScript

1.2

JavaScript

var caught = 5 * 5;

caught 5 5 25


21/61

6 1

var ten = 10;ten * ten; 100

l l l l

var var

catch22 $ _ $_$

=

=

caught; 25caught = 4 * 4;caught; 16;

Luigi 35

var luigisDebt = 140;luigisDebt = luigisDebt - 35;luigisDebt; 105

var

JavaScript

abstract boolean break byte case catch char class const continue debuggerdefault delete do double else enum export extends false final finally floatfor function goto if implements import in instanceof int interface long nativenew null package private protected public return short static super switchsynchronized this throw throws transient true try typeof var void volatilewhile with

char class JavaScript


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7 JavaScript

1.3

1.3.1

alert

alert("Good morning!");

l l l l

alert

alert

Math.max

Math.max(2, 4); 4

l l l l

JavaScript

Math.min(2, 4) + 100; 102

l l l l

2

1.3.2 prompt confirmconfirm

OK/Cancel OK true Cancel

false

confirm("Shall we, then?");l l l l


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8 1

prompt

prompt("Tell me everything you know.", "...");

1.3.3 print

alert

print

Web

JavaScript

X

print("X");

1.3.4

print 8 7

1.4

var theNumber = Number(prompt("Pick a number", ""));alert("Your number is the square root of " + (theNumber * theNumber));

Number Number prompt

String Boolean


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9 JavaScript

1.4.1

if

var theNumber = Number(prompt("Pick a number", ""));if (!isNaN(theNumber))

alert("Your number is the square root of " + (theNumber * theNumber));

l l l l

if !isNaN(theNumber)

true if

Number moo

NaN isNaN NaN

theNumber !isNaN(theNumber) true

else if

if (true == false)print("How confusing!");

elseprint("True still isn't false.");

l l l l

if/else

var num = prompt("Pick a number:", "0");

if (num < 10)print("Small");

else if (num < 100)print("Medium");

elseprint("Large");

num 10 10 small

10 if 100

10 100 Medium else

1.4.2 while do

0 12

print(0);print(2);print(4);print(6);


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10 1

1000

var currentNumber = 0;while (currentNumber


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11 JavaScript

Counter 1 10 0

do while

do

do {var input = prompt("Who are you?");

} while (!input);

l l l l

1.4.3

4 Tab

1.4.4 for

while counter

while counter

counter

JavaScript

for (var number = 0; number


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12 1

1.4.5

break break

20 7

for (var current = 20; ; current++) {if (current % 7 == 0)

break;}current; 21

l l l l

%

0

for break

for (var current = 20; current % 7 != 0; current++); // Do nothing.

l l l l

; //

1.4.6

coun-

ter = counter + 1 JavaScript counter += 1

result *= 2 result 2 counter - = 1 counter 1

counter += 1 counter - = 1 counter++ counter --

var result = 1;for (var counter = 0; counter < 10; counter++)

result *= 2;

l l l l

1.4.7 switch

if (variable == "value1") action1();else if (variable == "value2") action2();else if (variable == "value3") action3();else defaultAction();

switch JavaScript

C Java if


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13 JavaScript

switch(prompt("What is the weather like?")) {case "rainy":

print("Remember to bring an umbrella.");break;

case "sunny":print("Dress lightly.");

case "cloudy":print("Go outside.");break;

default:print("Unknown weather type!");break;

}

switch case switch

break sunny case

case sunny cloudy

break

1.4.8

fuzzylittleturtle fuzzy_little_turtle FuzzyLittleTurtle fuzzyLittleTurtle

JavaScript

JavaScript

Number

6

1.4.9

// Do nothing

// The variable counter, which is about to be defined, is going// to start with a value of 0, which is zero.var counter = 0;// Next, we loop. Hold on to your hat.while (counter < 100 / * counter is less than one hundred */)


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14 1

/* */ //

1.5

JavaScript

1.5.1 Undefined

var something;

var mysteryVariable;mysteryVariable; undefined

l l l lundefined

print alert undefined null undefined

null

something == undefine null == undefined true

1.5.2

false == 0; true"" == 0; true"5" == 5; true

JavaScript

/ * Every time we loop, we INCREMENT the value of counter,You could say we just add one to it. */

counter++;// And here, we are done.

l l l l


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15 JavaScript

null undefined null undefined true

false 0 NaN

false true 0 ""variable == false true

=== !==

=== false

null === undefined; falsefalse === 0; false"" === 0; false"5" === 5; false

if while for

0 "" null undefined false false

true

null

var maybeNull = null;// ... mystery code that might put a string into maybeNull ...if (maybeNull)

print("maybeNull has a value");

// maybeNull

maybeNull "" false

=== null ===false 0

1.5.3

JavaScript

"Apollo" + 5; "Apollo5"null + "ify"; "nullify""5" * 5; 25"strawberry" * 5; NaN


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16 1

NaN strawberry NaN NaN

NaN 5 NaN NaN==NaN false

NaN isNaN

+ * +

*

Number

NaN

Number("5") * 5; 25

1.5.4 && ||

&& ||

|| true

var input = prompt("What is your name?", "Kilgore Trout");print("Well hello " + (input || "dear"));

prompt inputnull "" false input || "dear"

input "dear"

&& || false

true ||

X X true X

false && X alert

false || alert("I'm happening!");false && alert("Not me.");


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2

1 alert print

2.1

function square(x) {return x * x;

}

square(12); 144

square x return x * x;

function function

while if

return return

return undefined

function power(base, exponent) {var result = 1;for (var count = 0; count < exponent; count++)

result *= base;

return result;}

power(2, 10); 1024


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18 2

2.1.1

future future

print("The future says: ", future());

function future() {return "We STILL have no flying cars.";

}

function

function

2.1.2

power

result

power result

var

x

xx

var x = "A";

function setVarToB() {x = "B";

}setVarToB();x; "B";

function setVarToC() {var x;x = "C";

}setVarToC();x; "B";


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19

return

undefined

2.1.3JavaScript

number factor

function multiplyAbsolute(number, factor) {function multiply(number) {

return number * factor;}

if (number < 0)return multiply(-number);else

return multiply(number);}

number multiply factor

number multiply number factor

multiplyAbsolute

JavaScript

var something = 1;{

var something = 2;// Do stuff with variable something...

}

// Outside of the block again...

//

//

something 2

if JavaScript

2


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20 2

2.1.4

function chicken() {return egg();

}function egg() {

return chicken();}print(chicken() + " came first.");

2.1.5

JavaScript function

a false a a false

null b

var a = null;function b() {return "B";}(a || b)(); "B"

(a || b)() () (a || b)

function

var a = null;(a || function(){return "B";})(); "B"

b


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21

function(){return "B";}

5

2.1.6

function createFunction() {var local = 100;return function(){return local;};

}

createFunction

(upwards Funarg problem)

JavaScript

createFunction()

100

function makeAdder(amount) {return function(number) {

return number + amount;};

}

var addTwo = makeAdder(2);addTwo(3); 5

2.1.7

alert("Hello", "Good Evening", "How do you do?", "Good-bye");

alert

Hello

JavaScript


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22 2

undefined

power

function power(base, exponent) {var result = 1;if (exponent === undefined)

exponent = 2;for (var count = 0; count < exponent; count++)

result *= base;return result;

}

print R2D2print("R", 2, "D", 2);

2.2

JavaScript

2.2.1

power

0 3

var number = 5;if (number < 10)

print("0", number);else

print(number);

10 0 0 2


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23

1 yes

2 print 0

zeroPad printZeroPadded print(zeroPad(5)) printZeroPadded(5)

3 0

function zeroPad(number, width) {var string = String(Math.round(number));while (string.length < width)

string = "0" + string;return string;

}

Math.round String

2.2.2

Purity

zeroPad printZeroPadded print

zeroPad print print


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24 2

2.2.3

power

function power(base, exponent) {if (exponent == 0)

return 1;else

return base * power(base, exponent - 1);}

while for for

JavaScript 10

JavaScript

power

power

1 5 3

13 1 3 5 15


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25

find 5

3 history

goal

|| start 5 false start 3

else {

var found = find(start + 5, "(" + history + " + 5)");if (found == null)

found = find(start * 3, "(" + history + " * 3)");return found;

}

function findSequence(goal) {function find(start, history) {

if (start == goal)return history;

else if (start > goal)return null;

elsereturn find(start + 5, "(" + history + " + 5)") ||

find(start * 3, "(" + history + " * 3)");}return find(1, "1");

}

findSequence(24); (((1 * 3) + 5) * 3)


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3

3.1 Emily

Emily 50

Drake

Igor

Emily

died 27/04/2006: Black Leclre born 05/04/2006 (mother Lady Penelope): Red Lion, DoctorHobbles the 3rd, Little Iroquois

Doctor Hobbles Penelope Lady 5


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28 3

Emily Spot

1 Spot

2

3 born died

4 born

5 died

12

3

Emily

3.2

3.2.1

JavaScript

length

var text = "purple haze";text["length"]; 11text.length; 11

null undefined


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29

3.2.2

length

var cat = {color: "gray", name: "Spot", size: 46};cat.size = 47;cat.size; 47delete cat.size;cat.size; undefined

size 46

size

undefined delete

=

var empty = {};empty.notReally = 1000;empty; {notReally: 1000}

var thing = {"gabba gabba": "hey", 5: 10};thing["5"]; 10thing[2 + 3]; 10delete thing["gabba gabba"];

var propertyName = "length";var text = "coco";text[propertyName]; 4

in

var chineseBox = {};chineseBox.content = chineseBox;"content" in chineseBox;


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30 3

3.2.3

in

in 6

Spot WhiteFang Spot

Asoka

var set = {"Spot": true};set["White Fang"] = true;delete set["Spot"];"Asoka" in set; false

3.2.4

1

120 120

var object1 = {value: 10};var object2 = object1;var object3 = {value: 10};

object1 == object2; true

object1 == object3; false

object1.value = 15;object2.value; 15object3.value; 10

true"content" in chineseBox.content; true


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31

object1 object2

object1 object2 object3 object1

JavaScript == truefalse

3.2.5

6

var mailArchive = {"the first email": "Dear nephew, ...","the second email": "..."/ * and so on ... */};/* ...*/};

var mailArchive = {0: "Dear nephew, ... (mail number 1)",1: "(mail number 2)",2: "(mail number 3)"};

for (var current = 0; current in mailArchive; current++)print("Processing email #", current, ": ", mailArchive[current]);

length

[]

var mailArchive = ["mail one", "mail two", "mail three"];

for (var current = 0; current < mailArchive.length; current++)print("Processing email #", current, ": ", mailArchive[current]);

0

1

1 0

0


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32 3

0 X X-1

for current


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33

toUpperCase

var mack = [];

mack.push("Mack");mack.push("the");mack.push("Knife");mack; ["Mack", "the", "Knife"]mack.join(" "); "Mack the Knife"mack.pop(); "Knife"mack; ["Mack", "the"]

push range result. push(i) result[i] = i pop push

join

3.3 Emily

ARCHIVE

for (var i = 0; i < ARCHIVE.length; i++) {var email = ARCHIVE[i];// Do something with this email...

}//

born

died

3.3.1

JavaScript

1

split

join


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34 3

email.split("\n")

3.3.2

born died

charAt x.charAt(0)

x.charAt(1) born

var paragraph = "born 15-11-2003 (mother Spot): White Fang";paragraph.charAt(0) == "b" && paragraph.charAt(1) == "o" &&

paragraph.charAt(2) == "r" && paragraph.charAt(3) == "n"; true

10

slice

paragraph.slice(0, 4) == "born"; true

startsWith

true false

function startsWith(string, pattern) {return string.slice(0, pattern.length) == pattern;

}

startsWith("rotation", "rot"); true

charAt slice pattern string

startsWith"Pip".charAt(250); """Nop".slice(1, 10); "op"

charAt "" slice

startsWith("Idiots", "Most honored colleagues") startsWith

var words = "Cities of the Interior";words.split(" "); ["Cities", "of", "the", "Interior"]


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35

pattern string slice pattern string

== false

3.3.3

1

2

3 died born

indexOf

slice

function catNames(paragraph) {var colon = paragraph.indexOf(":");return paragraph.slice(colon + 2).split(", ");

}

catNames("born 20/09/2004 (mother Yellow Bess): Doctor Hobbles the 2nd, Noog"); ["Doctor Hobbles the 2nd", "Noog"]

+2

split

3.3.4

var livingCats = {"Spot": true};

for (var mail = 0; mail < ARCHIVE.length; mail++) {var paragraphs = ARCHIVE[mail].split("\n");for (var i = 0; i < paragraphs.length; i++) {

var paragraph = paragraphs[i];if (startsWith(paragraph, "born")) {

var names = catNames(paragraph);for (var name = 0; name < names.length; name++)


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36 3

if ("Spot" in livingCats)print("Spot lives!");

elseprint("Good old Spot, may she rest in peace.");

in for

for (var cat in livingCats)print(cat);

3.3.5

startsWith catNames

function addToSet(set, values) {for (var i = 0; i < values.length; i++)

set[values[i]] = true;}

function removeFromSet(set, values) {for (var i = 0; i < values.length; i++)

delete set[values[i]];}

var livingCats = {Spot: true};

for (var mail = 0; mail < ARCHIVE.length; mail++) {

livingCats[names[name]] = true;}else if (startsWith(paragraph, "died")) {

var names = catNames(paragraph);

for (var name = 0; name < names.length; name++)delete livingCats[names[name]];

}}

}


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37

var paragraphs = ARCHIVE[mail].split("\n");for (var i = 0; i < paragraphs.length; i++) {

var paragraph = paragraphs[i];if (startsWith(paragraph, "born"))

addToSet(livingCats, catNames(paragraph));else if (startsWith(paragraph, "died"))

removeFromSet(livingCats, catNames(paragraph));}

}

addToSet removeFromSet set livingCats

addToSet livingCats

addCatsToCatSet

livingCatsset

function findLivingCats() {var livingCats = {"Spot": true};

function handleParagraph(paragraph) {if (startsWith(paragraph, "born"))

addToSet(livingCats, catNames(paragraph));else if (startsWith(paragraph, "died"))

removeFromSet(livingCats, catNames(paragraph));}

for (var mail = 0; mail < ARCHIVE.length; mail++) {var paragraphs = ARCHIVE[mail].split("\n");for (var i = 0; i < paragraphs.length; i++)

handleParagraph(paragraphs[i]);}

return livingCats;}

livingCats

findLivingCats

handleParagraph


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38 3

livingCats

findLivingCats

var howMany = 0;for (var cat in findLivingCats())

howMany++;print("There are currently ", howMany, " cats alive.");

3.3.6

(year)(month) (day)

var when = {year: 1980, month: 2, day: 1};

JavaScript new

var when = new Date(1980, 1, 1);

{}; new

6

// Produces a date object for the current time.new Date();//

// February (!) 1st, 1980new Date(1980, 1, 1);// March 30th, 2007, 30 seconds past 8:20new Date(2007, 2, 30, 8, 20, 30);

// 1980 2 1

// 2007 3 30 8 20 30

4 0

0 11 1

get

var today = new Date();print("Year: ", today.getFullYear(), ", month: ",

today.getMonth(), ", day: ", today.getDate());print("Hour: ", today.getHours(), ", minutes: ",

today.getMinutes(), ", seconds: ", today.getSeconds());


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print("Day of week: ", today.getDay());

getDay 4 get set

1970 1 1

var today = new Date();today.getTime(); 1266587282246

var wende = new Date(1989, 10, 9);var gulfWarOne = new Date(1990, 6, 2);wende < gulfWarOne; truewende == wende; true

// but be careful...wende == new Date(1989, 10, 9); false

// ...

< > = ==

true ==

false

==

false >= ==

var wende1 = new Date(1989, 10, 9),wende2 = new Date(1989, 10, 9);

wende1.getTime() == wende2.getTime(); true

1

12 7

getTimezoneOffset

(GMT)

new Date().getTimezoneOffset(); -60

3.3.7

"born 02/04/2001 (mother Clementine): Bugeye, Wolverine""died 27/04/2006: Black Leclre"

getDay getDate setDate


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extractDate

function extractDate(paragraph) {function numberAt(start, length) {

return Number(paragraph.slice(start, start + length));}return new Date(numberAt(11, 4), numberAt(8, 2) - 1, numberAt(5, 2));

}

Number 1

Number slice

1 Emily 1

8

3.3.8

true

death

addToSet removeFromSet

function catRecord(name, birthdate, mother) {return {name: name, birth: birthdate, mother: mother};

}

function addCats(set, names, birthdate, mother) {for (var i = 0; i < names.length; i++)

set[names[i]] = catRecord(names[i], birthdate, mother);}function deadCats(set, names, deathdate) {

for (var i = 0; i < names.length; i++)set[names[i]].death = deathdate;

}

catRecord

Spot Record born 15/11/2003 (mother Spot) ....

function extractMother(paragraph) {var start = paragraph.indexOf("(mother ") + "(mother ".length;var end = paragraph.indexOf(")");return paragraph.slice(start, end);


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"(mother " indexOf "(mother "

function findCats() {var cats = {"Spot": catRecord("Spot", new Date(1997, 2, 5), "unknown")};function handleParagraph(paragraph) {

if (startsWith(paragraph, "born"))addCats(cats, catNames(paragraph), extractDate(paragraph),

extractMother(paragraph));

else if (startsWith(paragraph, "died"))deadCats(cats, catNames(paragraph), extractDate(paragraph));}

for (var mail = 0; mail < ARCHIVE.length; mail++) {var paragraphs = ARCHIVE[mail].split("\n");for (var i = 0; i < paragraphs.length; i++)

handleParagraph(paragraphs[i]);}return cats;

}

catsfindCats

3.3.9

Emily

}

extractMother("born 15/11/2003 (mother Spot): White Fang"); "Spot"

function formatDate(date) {return date.getDate() + "/" + (date.getMonth() + 1) + "/" +

date.getFullYear();}

function catInfo(data, name) {var cat = data[name];if (cat == undefined)

return "No cat by the name of " + name + " is known.";


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catInfo return

4return

oldestCat

function oldestCat(data) {var oldest = null;

for (var name in data) {var cat = data[name];if (!("death" in cat) && (oldest == null || oldest.birth > cat.birth))

oldest = cat;}

if (oldest == null)return null;

elsereturn oldest.name;

}

if oldest

null oldest

3.4

3.4.1 arguments

arguments

0 1

var message = name + ", born " + formatDate(cat.birth) +" from mother " + cat.mother;

if ("death" in cat)message += ", died " + formatDate(cat.death);

return message + ".";}

// For example...catInfo(catData, "Fat Igor"); "Fat Igor, born 1/6/2004 from mother Miss Bushtail."


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length

arguments pushlength JavaScript

function argumentCounter() {return "You gave me " + arguments.length + " arguments.";

}argumentCounter("Straw man", "Tautology", "Ad hominem"); "You gave me 3 arguments."

print arguments

function add(number, howmuch) {if (arguments.length < 2)

howmuch = 1;return number + howmuch;

}

add(6); 7add(6, 4); 10

range 2 1

0 1 range

2

function range(start, end) {if (arguments.length < 2) {

end = start;start = 0;

}var result = [];for (var i = start; i


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3.4.2

print(sum(range(1, 10)));range sum

function sum(numbers) {var total = 0;for (var i = 0; i < numbers.length; i++)

total += numbers[i];return total;

}

sum(range(1, 10)); 55

3.4.3 Math

Math.max Math.min Math

max min

Math

max

JavaScript

Math Math.cos sin tan acos asin atan p e Math.PI Math.E

Math.pow

power Math.sqrt Math.max Math.min

Math.round Math.floor Math.ceil

3.4.4

Math

for (var name in Math)print(name);


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for (var name in ["Huey", "Dewey", "Louie"])print(name);

0 1 2 length push join

toString

6

for in


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