Errata

"var $new_comment" appears twice, first as a variable declaration, second line of the snippet, and again inside the nested block where it's used -- but also as a declaration ("var" occurs in both places).

Note from the Author or Editor:
triaged and now being tracked here:

https://github.com/semmypurewal/LearningWebAppDev/issues/47

"var $newUL = $("<ul>"); //create a new li element" should be:
"var $newUL = $("<ul>"); //create a new ul element"

Note from the Author or Editor:
This has been triaged as github issue #25

https://github.com/semmypurewal/LearningWebAppDev/issues/25

In the block for activating the third tab, the line to set the tab active refers to the second tab. This:
$(".tabs a:nth-child(2) span").addClass("active");
should be:
$(".tabs a:nth-child(3) span").addClass("active");

Note from the Author or Editor:
Noted here:

http://learningwebappdev.com/errata/chapter4/2014/04/20/chapter-4-tab-functionality-typo.html

The block that demonstrates refactoring the code for activating each tab omits the line from the previous version for clearing the main content ("$("main .content").empty();").

This line reappears on p. 137.

Note from the Author or Editor:
triaged and being tracked here

https://github.com/semmypurewal/LearningWebAppDev/issues/48

Missing semicolon at the end of the code sample.

Note from the Author or Editor:
Fixed for first ebook update.

Why are there two definitions for the function "organizeByTags", one inside of main() and one before it? They have different function signatures; does JavaScript support polymorphism?

If the first version of this function is #1 and the second version is #2, then #1 has a formal parameter and #2 does not. I don't know JavaScript; I would expect that the call to "organizeByTags(toDoObjects)" (in main()) would cause the interpreter to call #1, because the function signatures match. It doesn't, it calls #2. I'm guessing that this is a result of scoping, and polymorphism either doesn't exist in JavaScript or doesn't work the way I expect.

In short, I think the first definition of organizeByTags is just an error, and should be omitted.

Note from the Author or Editor:
This is definitely an error and is now being tracked here:

https://github.com/semmypurewal/LearningWebAppDev/issues/46

In the instructions for installing ntwitter, at the step for verifying the installation, should the command be "ls ../node_modules" and not "ls node_modules"? At that point the user is in the Twitter directory, but the module directory is one level removed.

Note from the Author or Editor:
This is an error. The node_modules directory will be in the same directory as the project's package.json, and since we didn't create a package.json file in the Twitter directory, the module will be installed one place above.

Since this doesn't directly affect the narrative, I've removed the ls command from the example in the first ebook update.

The code "as is" on page 200 produces an error. Since tweet is an object, we can't use tweet.indexOf. I got it to work by replacing it with tweet.text.indexOf, which is hinted at on page 199 under "Using the indexOf function to find words."

Note from the Author or Editor:
being tracked here

https://github.com/semmypurewal/LearningWebAppDev/issues/32

The text says to run the server from the app directory and the command line to run the server shows "vagrant $ node app.js". Should this be "node server.js", running server.js in the app directory?

Note from the Author or Editor:
This issue has been noted here: http://learningwebappdev.com/errata/chapter6/2014/04/12/chapter-6-express-version-4.html

It is fixed in the latest ebook update, which will be pushed soon!

I believe the if statement shouldn't have the = in >=.
"if (tweet.text.indexOf("awesome") >= -1)"

This executes the if statement when we found awesome and when we didn't as well. The code back in chapter 6 does not have the =, too.

Note from the Author or Editor:
Being tracked here:

https://github.com/semmypurewal/LearningWebAppDev/issues/34