Errata

The code samples provided at the following address contain numerous errors:

http://examples.oreilly.com/9780596517748/

I'm up to Chapter 4 and have found at least six examples so far where I have had to modify the code samples to match what is in the book so that they run. The good news is that errors have been picked up and corrected in the book, but the code samples have not been modified to match.

As I'm reading the mobi version in Kindle, there is no way to copy and paste the code samples directly from the book (this is disabled for me), so I am reliant on the external code sample files to be able to work through the examples.

Don't get me wrong, this is an excellent book - but the publisher's lack of attention in not updating the source code is disappointing.

Please update for future readers :)

Where an object is thrown inside the else clause of the function by, the value of the message property ends with an erroneous semicolon ? this should be omitted.

Note from the Author or Editor:
In the middle of page 81, the semicolon after
+ name
should be deleted.

In the infix operator diagram, to the right of the 'logical and' oval, the line meets the vertical line at a right angle. It should be curved upwards to indicate that this branch goes to the end of the diagram.

Note from the Author or Editor:
In the infix operator diagram on page 17 and also page 129, the track exiting (&&) should curve up to join instead of running straight into the line.

Replace

if (Array.prototype...

with

if (Object.prototype...

Wrap the invocation in parens.

var myObject = (function () {
and
}());

At the bottom of the page there are two lists of operators. Please remove period from the first list and insert period after the ] in the second list.

, ; : { } and so on

) ] . ++ --

Replace the second code fragment with:

if (Array.prototype.toString.apply(my_value) === '[object Array]') {
// my_value is truly an array!
}

The var my_regexp statement in the middle of the page should be all on one line, and the line should end with a semicolon.

var my_regexp = new RegExp(I don't dare try to retype that stuff));

Both string literal syntax diagrams incorrectly forbid an escaped character immediately before the closing quote. This is immedately contradicted by "\u0041" in the first example on page 9, May 2008 First Edition bought at Borders.

-----
Not sure I like the lightweight paper but thin is good.
-----
I suspect folks check "Post errata anonymously"
on autopilot as I did, just hitting each item
of the form in sequence. Try radio buttons.

Note from the Author or Editor:
The string literal diagram needs correction.

The text says:

var digits = '0123456789';
var a = digits.split('', 5);
// a is ['0', '1', '2', '3', '456789']

a is actually ['0', '1', '2', '3', '4']

Note from the Author or Editor:
// a is ['0', '1', '2', '3', '4']

The "BETTER EXAMPLE" is broken. The fix to the first printing was still incorrect. The example should read

var add_the_handlers = function (nodes){
var i;
for( i=0; i < nodes.length; i += 1 )
{
nodes[i].onclick = function(i){
return function () {
alert(i);
};
}(i);
}
};

That works with IE and Firefox.
This mistake is pretty bad, I would have hoped the author tested the code! Thanks

Note from the Author or Editor:
nodes[i].onclick = (function (i) {
return function (e) {
alert(i);
};
}(i));

The wrong quote is used here. It should be the ASCII apostrophe: 'Q'

Table C-1 does not jive with Options listed at http://www.jslint.com/#options ( and the JSLint Options listed at http://www.jslint.com/lint.html ) -- the latter has more options than Table C-1

In particular, Table C-1 is lacking:

newcap
css
indent
onevar
predef
regexp
safe
sidebar
strict
sub

Furthermore, Table C-1 lists "glovar," which does not appear in the JSLint Options listed at http://www.jslint.com/lint.html

Finally, there are 28 options listed in the JSLint Options at http://www.jslint.com/lint.html while there are only 26 at http://www.jslint.com/#options

Note from the Author or Editor:
Remove the line that starts with glovar.

The edition of the book I have has a single character instead of the required `\u' for each of the four separate UniCode hex enumerations in the regular expression. This single character resembles a crescent moon and may be (or: is similar to) \u02D8.

Also, why is there a ' (single quote) character in the regular expression? ( It appears between FFFD and the closing ] )

In summary, the regex for var doubled_words should use the "simple letter class" from the first sentence of the first paragraph on the page.

Note from the Author or Editor:
The example has been mangled. The expression inside the [ ] should match the expression in the page's first sentence.

On page 33, the code at the top of the page includes `return this;' while the similar code at the bottom of the page is missing this statement.

Missing commas - replace last section with:

escapee = {

'"': '"',

'\\': '\\',

'/': '/',

b: 'b',

f: '\f',

n: '\n',

r: '\r',

t: '\t'

},

the following:

new RegExp("\"(?:\\.|[^\\\\\\\"])*\"", 'g'))

should be the following:

new RegExp("\"(?:\\\\.|[^\\\\\\\"])*\"", 'g'))

This error is in the Print version and the Safari Online version. On Page 54, the second code block where the function "cat" is defined, the get_name method does not have a closing parenthesis.

var cat = function (spec) {
spec.saying = spec.saying || 'meow';
var that = mammal(spec);
that.purr = function (n) {
var i, s = '';
for (i = 0; i < n; i += 1) {
if (s) {
s += '-';
}
s += 'r';
}
return s;
};
that.get_name = function ( ) {
return that.says( ) + ' ' + spec.name +
' ' + that.says( );
return that;
};



The get_name function should be:

that.get_name = function ( ) {
return that.says( ) + ' ' + spec.name +
' ' + that.says( );
};
return that;

Note from the Author or Editor:
that.get_name = function () {
return that.says() + ' ' + spec.name +
' ' + that.says( );
};

Hello,

The third source code block in this section on Safari Books Online has:

"seqer.set_prefix('Q';)"

replace with:

"seqer.set_prefix('Q');" //move semicolon outside of parenthesis.

It is easy to figure out, but still confusing if you Cut+Paste the code and it wont run.

The last line of the example reads:
}());
that is one closing parenthesis too many. It should be
}();
With the extra parenthesis the example will not run.

The last line of code uses a getter:
myObject.getValue()
This getter has not been defined. So access the property directly as on the previous page:
myObject.value

the last line of the code example reads:
document.writeln(myObject.getValue()); // 6

this does not work, since the getValue() method is not defined on myObject. Safari 3.1.2 reports the error "TypeError: Value undefined (result of expression myObject.getValue) is not object." and Firefox 3 reports "Error: myObject.getValue is not a function".

The line should read:
document.writeln(myObject.value);
like in the code example on the previous page.

This line
seqer.set_prefix('Q';)
should be
seqer.set_prefix('Q');

The book reads: "The property whose value is 'shi' has its key changed from '4' to '3'."

It should read: "from '3' to '2'."

There are two errors in this code example:
1) The definition of serial_maker is finished with () which invokes the anonymous function. That makes the next line: var seqer = serial_maker(); erroneous since serial_maker is not the function but the object returned by the anonymous function.
2) once the previous error is fixed the two lines:
seqer.set_prefix = 'Q';
seqer.set_seq = 10000;
should change to:
seqer.set_prefix('Q');
seqer.set_seq(10000);

Typo: Replace 'ceiling' by 'ceil':

Number.method('integer', function ( ) {
return Math[this < 0 ? 'ceil' : 'floor'](this);
});

Missing
};
before
return that;
at end of function definition.

Note from the Author or Editor:
In the middle of the page.

that.get_name = function () {
return that.says() + ' ' + spec.name +
' ' + that.says();
};
return that;
}:

The code reads:
stooge["first-name"] // "Joe"

However, on the previous (p. 20) the property "first-name" is set to "Jerome". To be consistent, both values should be the same.

Note from the Author or Editor:
It should be

stooge["first-name"] // "Jerome"

Hi,

Revision: First Edition
Page: 90

The 3rd paragraph on this page, which discusses string.replace, has the following code sample:

var oldareacode = /\((\d{3})\)/g;
var p = '(555)666-1212'.replace(oldareacode, '$1-');
// p is '555-555-1212'

The given answer is incorrect. var p is 555-666-1212.

Thanks for such a good book that is informative, intelligent and non-patronising. I hope O'Reilly and the author will publish more books like this!

Mark

The name of an object is missing a letter
reads: number_object
should be: numbers_object

Note from the Author or Editor:
There are two places in the paragraph where number_object should be replaced with numbers_object

The regular expression given in the example:

var doubled_words = /[A-Za-z\u00C0-\u1FFF\u2800-\uFFFD'\-]+\s+\1/gi;

does not include any capturing parens to allow the \1 backreference to work. I believe the corrected version should be:

var doubled_words = /([A-Za-z\u00C0-\u1FFF\u2800-\uFFFD'\-]+)\s+\1/gi;

In the press them all together regex, there's an extra ? (between the ) and ( )
... a-z]+)?(?::( ...

or there's a ? missing from the
var parse_url = ... on page 66.

Note from the Author or Editor:
Replace +)?(?:: with +)(?:: by deleting the ? between the parens.

tryIt should be try_it

return this.says + ' ' + this.name + ' ' + this.says;

apparently should be:

return this.says() + ' ' + this.name + ' ' + this.says();

like the similar correct example on page 49.

The code listing on page 47 of Crockford's book Javascript - The Good Parts is missing a semicolon, namely:

// Create a new object that inherits from the
// constructor's prototype

var that = Object.beget(this.prototype)

From the context, it seems this part:

for (j = 0; j < n; j += 1) {
a[j] = 0;
}

should be:

for (j = 0; j < n; j += 1) {
a[j] = initial;
}

- otherwise the "initial" parameter is quite pointless.

Location: 4th line of code in middle of page

Description: The code listing
Javascript - The Good Parts is missing a semicolon, namely:

// Create a new object that inherits from the
// constructor's prototype

var that = Object.beget(this.prototype)

Location: first code example

Description: return this.says + ' ' + this.name + ' ' + this.says;

apparently should be:

return this.says() + ' ' + this.name + ' ' + this.says();

like the similar correct example on page 49.

First paragraph, lines 8 and 12 (see line 2)

The name of an object was missing a letter

was: number_object
now reads: numbers_object

There are two places in the paragraph where number_object should be replaced with
numbers_object

Location: Code block after 1st paragraph

Description: From the context, it seems this part:

for (j = 0; j < n; j += 1) {
a[j] = 0;
}

should be:

for (j = 0; j < n; j += 1) {
a[j] = initial;
}

- otherwise the "initial" parameter is quite pointless.

Location: Bottom footnote

Description: In the press them all together regex, there's an extra ?
(between the ) and ( )
... a-z]+)?(?::( ...

or there's a ? missing from the
var parse_url = ... on page 66.

Notes from the Author: Replace +)?(?:: with +)(?:: by deleting the ?
between the parens.

3rd paragraph, regular expression example
The regular expression given in the example:

var doubled_words = /[A-Za-zu00C0-u1FFFu2800-uFFFD'-]+s+1/gi;

does not include any capturing parens to allow the 1 backreference to work. Corrected version
now reads:

var doubled_words = /([A-Za-zu00C0-u1FFFu2800-uFFFD'-]+)s+1/gi;