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From https://github.com/raganwald/javascript-allonge-six/blame/master/manuscript/markdown/1.ComposingData/tail.md#L75

Several, in fact, fast algorithms is a very highly studied field of computer science.

I found this sentence difficult to read. Could you use a period or m-dash instead of the comma?

Several, in fact. Fast algorithms is a...

Several, in fact—fast algorithms is a...

Thanks for the great book. I am enjoying it!

filter is a degenerate case of map*.

It looks like this text was copied to "Reassignment" from "rebinding," so it references itself.

The memoized code recipe at the bottom of page 216 (pdf version, 4/14/16) fails when combined with subsequent code samples.

I believe that the following line is the culprit:
const key = JSON.stringify(this, args);

I got it working with:
const key = JSON.stringify.apply(this, args);

First, thanks for releasing JavaScript Allonge Six edition free to read online! I just started reading it and I think I'm going to have to buy a copy.

I think I found a bug in the first function in the 'call by sharing' section. The function

(value) => ((ref1, ref2) => ref1 === ref2)(value)

is described as always returning true, but actually it always returns false because the inner function is only applied to (value), not (value, value).

Probably warrants an explanation of the difference in semantics.

The filterIteratorWith function on page 156 (pdf, 4/14/16) did not work for me. I believe the const declaration in the do block is the culprit. I got it to execute by making a let declaration for done and value before the do block:

 const filterIteratorWith = (fn, iterator) =>
    () => {
      let done, value;
      do {
        ({done, value} = iterator());
      } while (!done && !fn(value));
      return {done, value};
    }

I'm new to JS so it's entirely possible I'm just not understanding how the copy function should work. However, in my Firefox browser (which had no issues with any example up to this point in the text), copy does not seem to work at all.

Here's a code snippet displaying the issue:

>> parentList
<- Object { first: "one!", rest: Object }
>> copy(parentList) // does not have any result
>> var thing = copy(parentList);
>> thing
<- undefined

Translation to string keys.

Compare value keys to identity keys, e.g. parallel literals, identity after mutation.

rewrite the mapWith recipe for performance, touch on [first, ...rest] being slow.

I just finished working through your extension of a queue into a dequeue – page 197 of the most recent "printing" on Leanpub. When I ran your code examples, I encountered a few hiccups:

1. The extend function is not used in the code sample.
2. The for loops in extend and the pushHead method (found in the return statement of Dequeue) declare the name-binding i with const instead of let; Thus, subsequent reassignments of i fail.

Additionally, I'm not sure what purpose INCREMENT serves. Because it is constant, it is not responsive to the state of the data structure. This results in sparse arrays at times.

Instead of merely pointing these issues out, I also attach a text document containing revisions to your code sample, which I believe implement a dequeue. I made two major revisions beyond addressing the issues I enumerate above:

1. My queue has a method called expose which I found useful for debugging.
2. I declare increment with let, and reassign it in the if block of the pushHead method.
   Finally, note that the format of the text document is .org, not .js. I used org mode's code blocks and the babel transpiler to display my REPLs output at the bottom of the document

First of all thank you for this wonderful book! I bought it after having read about half of it on learnpub. It is the best javascript book I found so far!

Under the subsection the problem with state of Stateful Method Decorators section, the code

musician.fullName() //=> Raymond Smullyan

is incorrect - the statement actually returns TypeError: Cannot read property 'fullName' of undefined. This is because once being called for the 2nd time returns undefined and hence musician is undefined.

Model: 'Exception: SyntaxError: invalid assignment to const redoStack'

if (!redoStack.isEmpty()) {
            redoStack = Stack()
          }

I got a different return value for the code sample:

plus1(undefined);
//=> NaN

not null

JSFiddles, gists,a repo, files in the repo, something (anything!) that collects samples into coherent chunks that people can download and use.

All of the headaches that go with manually freeing resources.

Target: Functions chapter

More important than introducing symbols

We found the following problems with your epub file:\n

• Error while parsing file 'Duplicate ID 'fn-mp''.

• Error while parsing file 'Duplicate ID 'fn-mapWith''.

• Error while parsing file 'Duplicate ID 'fn-wellactually''.

• Error while parsing file 'Duplicate ID 'fn-but''.

• Error while parsing file 'Duplicate ID 'fn-colours''.

• Error while parsing file 'Duplicate ID 'fn-ESdotlater''.

• You have created a crosslink to #policies but that ID does not exist

• You have created a crosslink to an id that does not exist

• You have created a crosslink to #once but that ID does not exist

• You have created a crosslink to #partial but that ID does not exist

• You have created a crosslink to #ellipses but that ID does not exist

• You have created a crosslink to #tap-methods but that ID does not exist

• You have created a crosslink to #pojoseverywhere but that ID does not exist

• You have created a crosslink to #binding but that ID does not exist

• You have created a crosslink to #modules but that ID does not exist

• You have created a crosslink to #reducing%20coupling but that ID does not exist

• You have created a crosslink to #consumers but that ID does not exist

• You have created a crosslink to #arrays but that ID does not exist

e.g.

const mapIterableWith = function * (fn, iterable) {
  for (const element of iterable) {
    yield fn(element);
  }
};

Code sample top of page 151 (pdf 4/14/16); The object eachIteration is called in the while statement without being declared.

• streamline the code
• emphasize that this is an example of a way of thinking
• reference the way Ruby has a module for iterations

https://gist.github.com/rauschma/73e5f86a595b7709f39e

isEmpty: () =>
return queue.tail < queue.head

In the subsection memoizing recursive functions, the phrase "functional expressions" appears a few times. Perhaps "function expression" auto-corrected to functional expression?