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The latest version of the book is P1.0, released about 2 years ago. If you've bought a PDF of the book and would like to update it to this version (for free), visit your home page.

By default this page displays the errata for the latest version of the book. If you have a previous version, select it here:

If you've found a new error, please submit it.

  • Typo
  • Tech. error
  • Suggestion
  • Maybe next edition
  • Not a problem
  • Reported in: P1.0 (20-Apr-18)
#83028
PDF page: 15

In the second code block on the page, the call should be to function yell instead of greet:
greet('Pankaj');--Jason Chapin

  • Reported in: P1.0 (12-Apr-20)
#86569
Paper page: 22

"affectively"[sic] should be "effectively"

  • Reported in: B3.0 (07-Apr-18)
#82968
PDF page: 25
Last paragraph, 4th sentence: change "... you can rely instead OF the language feature to limit scope." to "... rely instead ON the ...". Actually ...more...
  • Reported in: B3.0 (07-Apr-18)
#82972
PDF page: 25
My apologies. The above typos for pages 25 and 26 were for a different book with a similar name. Please remove all these messages for me.--George S. C...more...
  • Reported in: B3.0 (07-Apr-18)
#82969
PDF page: 26

"code is easier to reason" -> "code is easier to reason about"--George S. Cowan

  • Reported in: P1.0 (20-Apr-18)
#83027
PDF page: 33
The JavaScript method for adding an item to the beginning of an array is written as being `array.shift()`, when it is actually `array.unshift()`. The ...more...
  • Reported in: P1.0 (15-Jan-20)
#86258
Paper page: 36
In second sentence of second paragraph, change... "Turns out, sorting by name a second time..." ... to... "Turns out, sorting by years a seco...more...
  • Reported in: P1.0 (09-May-18)
#83078
PDF page: 41

The 3rd line of the 2nd paragraph:
they are really are that flexible

You should omit one of "are" s
--Naoki Hashimoto

  • Reported in: P1.0 (12-Nov-19)
#86000
PDF page: 46
you should update the output for: anotherBook is changing it const anotherBook = { title: 'Another book', year: 2016, }; Object.assign(defaults...more...
  • Reported in: P1.0 (12-Apr-20)
#86571
Paper page: 50
"Deciding when to use proposed syntax is a matter of preference." You may wish to refer to the website caniuse.com where one can check the support ...more...
  • Reported in: P1.0 (13-Apr-20)
#86576
Paper page: 50

another site for checking feature availability is
kangax.github.io/compat-table/es2016plus/

  • Reported in: P1.0 (09-May-18)
#83077
PDF page: 71

The 1st line of the 2nd paragraph from the bottom:
means means -> means
--Naoki Hashimoto

  • Reported in: P1.0 (25-Jul-18)
#83416
PDF page: 80
The following statement strikes me as just a bit too stringent: "Though you can chain multiple ternary expressions together, you should avoid doing so...more...
  • Reported in: P1.0 (25-Jul-18)
#83417
PDF page: 80
Regarding #82416, my example code got mangled even more than I anticipated. Please see o10c7gda on jsfiddle for a formatted example. Thanks! --Ted...more...
  • Reported in: P1.0 (13-Apr-20)
#86573
Paper page: 83
"So if one value in an || check returns true, you get that truthy value and not true." perhaps reword to something like "When a truthy value is foun...more...
  • Reported in: P1.0 (13-Apr-20)
#86574
Paper page: 86

Soon(?) you will be able to use the optional chaining operator (?.) and the nullish coalescing operator (??) for even more efficient short circuiting.

  • Reported in: P1.0 (13-Apr-20)
#86575
Paper page: 90
const assignedFunction = function() { } Finally! I've been holding my breath since Tip 3 in Chapter 1 for Joe to apply the benefits of block-scopi...more...
  • Reported in: P1.0 (09-May-18)
#83076
PDF page: 94

the 1st line of the 2nd paragraph from the bottom:
the size array -> the size of array/the array size ?--Naoki Hashimoto

  • Reported in: P1.0 (15-Nov-19)
#86011
PDF page: 103

what the hell is a 'Colbert" regarding truthiness. consider your non-american readers. p--j

  • Reported in: P1.0 (13-Apr-20)
#86577
Paper page: 144

'wvoquine' on page 144 vs. 'wvoquie' on pages 145 and 146. might be a typo.
V.v.O.Quine to wvoquine? Hobbes to Hobbs? Engels to Eagles?

  • Reported in: P1.0 (09-May-18)
#83075
PDF page: 194

In the second example from simple.js:
[...getCairoTrilogy] -> [...getCairoTrilogy()]

(you should add parentheses)--Naoki Hashimoto

  • Reported in: P1.0 (09-May-18)
#83074
PDF page: 214

on 2nd paragraph line 4:
to to reduce -> to reduce--Naoki Hashimoto

  • Reported in: P1.0 (15-Apr-20)
#86595
Paper page: 218

Para. 5: "... but it isn't accessible by JavaScript in the browser." -- please clarify.