Historical errata for CoffeeScript

x ?= y x = y unless x? if (typeof x != ‘undefined’ && x !== null) {x=y}

If I understand well the ?= operator, the condition in the javascript column is inversed. It should be:

if (typeof x 'undefined' || x = null) {x=y}

On question 6, I believe that

“@x refers to variable that obeys context rules”

should be

“@x refers to a variable that obeys context rules”

In the Tribble.coffee example, the method `Tribble.makeTrouble()` doesn’t return output. When compiled to JavaScript, the `for` loop doesn’t run in the proper context (which should be `this`).

“No scope for ‘for’”
Is it worth noting that in the butler example if no entity in murderMysteryCharacters has the occupation of ‘butler’ that the last entity in the collection gets blamed?

«CoffeeScript’s of is equivalent to JavaScript’s ’in.»
There’s an extra apostrophe, or single quote, before “in”.

«Think of it this way: Values live in an object, while you have keys of an object.»

The typeface/style of ‘in’ and ‘of’ made me think you were alluding to the operators of the same name, when I believe this was supposed to indicate emphasis.

If we were to draw a parallel with the operators, should we not be encouraged to think that values live ‘in’ an array?

Add a pinch of extra confusion when the sentence preceding that quote states that “CoffeeScript’s of is equivalent to JavaScript’s in”; however, JavaScript’s “in” returns keys, not values.

My suggestion is to display ‘in’ and ‘of’ in italics.

«of and in lead double-lives as operators»

I thought this worthy of a simple example block; I almost skimmed over the paragraph.

murderMysteryCharacters =
‘Colonel Mustard’: ‘colonel’
‘Professor Plum’: ‘professor’
fruits = [ ‘apple’, ‘banana’, ‘cherry’, ‘tomato’ ]
vegetables = [ ‘asparagus’, ‘broccoli’, ‘carrot’, ‘turnips’ ]
console.log ‘Professor Plum’ of murderMysteryCharacters
console.log ‘Ms. Priss’ of murderMysteryCharacters
console.log ‘apple’ in fruits
console.log ‘tomato’ in vegetables

The ‘message.match’ regex triggers syntax highlighting that extends too far; the ‘extend = (a, others…)’ block’s highlighting is wrong.

I believe it should be a
console.log greeting ‘arguments’

Clone of #47072 — other places where example style is off:
«when isInteger(960 / num))»
“/ num))” appear in italics

Clone of #47072 — other places where example style is off:
«radius: -> @width / 2»
The text at “/ 2” until the end of the sample block appears in italics

«So what’s the value of a loop? An array of the the loop’s iteration values, naturally.»
“the the”

You might want to let us know how to quit out of the Node console… ‘quit’, ‘end’, ‘exit’ all produced errors.

“prooperties” should be “properties”.

For exercise 4.7.1, I think it might be better to use global instead of exports - I found it confusing when I typed the code into a file chapter4.coffee, ran it, and got “ReferenceError: aphorism is not defined”.

“That means that the while the parentheses…” should be “That means that while the parentheses…”.

“Here’s how the game looks when it all comes together:” should refere to Figure 5 which is on the next page.

You wrote “prooperties” instead of “properties” at the fourth line before the end of the page.

on page 31, why not use this as the definition for the function inRange

inRange = (x, y) ->
0 <= x <= GRID_SIZE and 0 <= y <= GRID_SIZE

Then on the top of page 32 you can get rid of the (–1)s to make the old inRange work:

else if not inRange x, y #was x-1, y-1 before
console.log “Each coordinate must be between 1 and #{GRID_SIZE}”

Thanks. I’m enjoying the book so far,
Tim

“prooperties” is misspelled.

The code coloring is off, when talking about class inheritance of the shapes.

The ‘s’ is missing in ‘Windows’ where it reads “While the Node team is working to improve their support for Window”

This is specific to the Mobi version of the book.

It reads “See the sidebar … for an explanation …” but there is no “sidebar”. The explanation is just inline and follows immediately. There’s no space for a sidebar on an eReader :)

“Well, console.log returns null, which gets coerced to false
by condition checks” -> Should that actually be “console.log returns undefined”?

coffee> console.log console.log “test”
test
undefined

“those inRange checks ensure that both ends a potential
word are within the grid” should be “both ends of a potential word”

“and Resig has become of the world’s most famous programmers” should be “and Resig has become one of the world’s most famous programmers”

Everywhere I’ve read about in browser compilation using coffee-script.js says that you should include it after any coffeescript. You’re including it before the coffeescript files, is this a mistake?