# Release 2018-03-02

* Chapter “New regular expression features”:
    * Fixed a bug in copyWithIgnoreCase()
    * New function: copyAndEnsureFlag()

# Release 2016-03-02

* New: per-chapter TOCs
* Chapter “Callable entities in ECMAScript 6”: many small improvements
* Chapter “Arrow functions”: several improvements and major rewrites of three sections:
    * Arrow functions bind very loosely
    * Returning object literals
    * Immediately-invoked arrow functions

# Release 2016-11-19

* Chapter “Parameter handling”: better overview section, a few minor improvements.
* Chapter “Destructuring”: various smaller improvements and fixes.
* Chapter “Proxies”: new section “Pitfall: not all objects can be wrapped transparently by proxies”.

# Release 2016-11-07

* Major rewrite of chapter “Template literals”.
* Numerous smaller improvements in chapter “Variables and scoping”.
* Completely new overview section for chapter “Generators”.
* New section “Three ways of understanding Promises” in chapter “Promises”.

# Release 2016-10-29

Many smaller fixes and improvements in the following chapters:

* New string features
* Symbols

# Release 2016-09-09

Numerous smaller improvements in chapters 1–5.

# Release 2016-04-11

* New Sect. “Tips for error handling” in Chap. “Promises for asynchronous programming”
* New Sect. “Throwing an exception from a generator” in Chap. “Generators”
* Made sure destructuring assignments that start with a curly brace are correct everywhere (you need to parenthesize the whole expression, not just the pattern).
* Complete rewrite of Sect. “Traversing properties in ES6” in Chap. “New OOP features besides classes”
* Fixed terminology: some operations “traverse” properties (for-in, Object.keys(), etc.); iterators “iterate over” the “items” of an iterable.
* Fixed many errata.
* Major rewrite of the section on `Promise.resolve()` in Chap. “Promises for asynchronous programming”
* Major rewrite of Sect. “ES6-compatible Promise libraries” in Chap. “Promises for asynchronous programming”


# Release 2016-04-05

* Added a short TOC.
* Improved intro for Sect. “Composing Promises” in Chap. “Promises for asynchronous programming”
* New entry “How can I use ES6 today?” in Chap. “FAQ: ECMAScript 6”
* New Sect. “Arrow functions versus `bind()`” in Chap. “Arrow functions”

# Release 2016-03-28

* New chapter: “An overview of what’s new in ES6”
* New Sect. “Other ways of creating Promises” in Chap. “Promises for asynchronous programming”

# Release 2016-03-23

* New Sect. “Removing holes from Arrays” in Chap. “New Array features”
* Complete rewrite of Sect. “Creating Arrays filled with values” in Chap. “New Array features”
* New Sect. “Line terminators in template literals are always LF (`\n`)” in Chap. “Template literals”
* New Sect. “Benefit: compact bundling, no custom bundle format” in Chap. “Modules”

# Release 2016-03-13

* Substantial rewrite of Chap. “Promises for asynchronous programming”. New sections: “Parallel computations via `Promise.all()`” and “Common Promise mistakes”
* New Sect. “Imports and exports must be at the top level” in Chap. “Modules”
* FAQ in Chap. “Generators”: “Why use the keyword `function*` for generators and not `generator`?”
* FAQ in Chap. “Generators”: “Is `yield` a keyword?”
* FAQ in Chap. “Maps and Sets”: “When would I use an object as a key in a Map?”
* Explained one more use case for WeakMaps: “Managing listeners” (Chap. “Maps and Sets”)
* New Sect. “No separators between members of class definitions” in Chap. “Classes”
* New Sect. “Example: an iterable version of `exec()`” in Chap. “New regular expression features”

# Release 2016-02-23

* Syntax highlighting finally upgraded to ES6 (esp. template literals look much better now).
* New Sect. “Examples of name clashes in JavaScript’s standard library” in Chap. “Symbols”
* Major rewrite of Sect. “Symbols as keys of properties” in Chap. “Symbols”
* New Sect. “The `name` property of functions” in Chap. “Callable entities in ECMAScript 6”
* Complete rewrite of Sect. “Iterating over property keys in ES6” in Chap. “New OOP features besides classes”.
* More content in Sect. “Examples of destructuring” of Chap. “Destructuring”.
* New Sect. “Pitfall: `Object.freeze()` is shallow” in Chap. “Variables and scoping”.
* More examples for tagged template literals in Chap. “Template literals”.
* Many small improvements and corrections.

# Release 2016-02-14

* New chapter 17: “The for-of loop” (I moved the existing material there)
* Rewrote the intro for the chapter on Promises.
* New glossary entries: “Strict mode versus sloppy mode”, “Bindings and environments”
* Mentioned that the enumerate trap was recently removed (proxies).
* New Sect. “Sources of this book” in Chap. “What you need to know about this book”
* Example “Why are per-iteration bindings useful?” in Chap. “Variables and scoping”.
* Lots of small fixes, improvements and additions.

# Release 2016-01-18

* New Sect. “Simple mixins” in Chap. “Classes”
* Major rewrite of Chap. “Callable entities in ECMAScript 6”
* New Sect. “Classes have inner names” in Chap. “Classes”
* New material on trailing commas in object literals in Chap. “Coding style tips for ECMAScript 6”
* New sections in Chap. “Template literals”: Sect. “Text templating with untagged template literals” and Sect. “A tag function for HTML templating”
* New Sect. “Example: assembling regular expressions” in Chap. “Template literals”
* Improved overview for Chap. “Iterables and iterators”
* Chap. “Symbols”: improved overview (at the beginning) and summary (at the end)
* Better introductory paragraph for Sect. “What is tail call optimization?” in Chap. “Tail call optimization”
* Significant rewrite of Sect. “Is ES6 bloated?” in Chap. “FAQ: ECMAScript 6”

# Release 2016-01-12

* Chap. “Classes”: New FAQ entry “How do I determine whether a function was invoked via `new`?”
* Chap. “Callable entities in ECMAScript 6”: major rewrite.
* Chap. “Classes”: New FAQ entry “How are classes different from traditional functions?”
* Complete rewrite of Sect. “Managing the private data of classes” in Chap. “Classes”.
* Major rewrite of Sect. “The details of subclassing” in Chap. “Classes”.
* New Sect. “Recommendation: avoid mixing default exports and named exports” in Chap. “Modules”
* New Sect. “Benefit: dead code elimination during bundling” in Chap. “Modules”
* New Sect. with some new content: “Why a new approach to importing?” in Chap. “Modules”
* Significant rewrite of Sect. “Advantages of ECMAScript 6 modules” in Chap. “Modules”
* Better intro for Sect. “The species pattern” in Chap. “Classes”
* Minor improvements in Chap. “Metaprogramming with proxies”
* Much improved introduction in Sect. “Implementing tag functions” of Chap. “Template literals”
* I switched all code to “prefer const” (from “prefer let”). This is a massive change. Let me know if you spot any errors: http://exploringjs.com/#errata

# Release 2016-01-07

* Chap. “First steps with ECMAScript 6”: major rewrite of Sect. “From `var` to `let`/`const`”.
* Chap. “First steps with ECMAScript 6”: new sections on new string methods and new Array methods.
* Complete rewrite of symbol FAQ entry “Can I use symbols to define private properties?”
* Major rewrite of the section on WeakMaps.
* New Sect. “The numeric range of Array indices” in Chap. “New Array features”.
* Various smaller improvements in Chap. “Generators”.
* Various smaller improvements in Chap. “Symbols” (e.g. a table in the overview at the beginning)
* Major rewrite of Sect. “Overview” of Chap. “Destructuring”.

# Release 2016-01-01

* A few minor fixes.

# Release 2015-12-30

Announcement:

I have written a new book: “Setting up ES6”. Everyone who owns “Exploring ES6” right now can get a free copy via this coupon (valid until January 11): [sent via email to owners]

As a step towards a stable version 1.0 of “Exploring ES6”, along with a print version (hopefully by mid-2016), I have moved Chap. “Deploying ES6” to the new book. Apologies for the inconveniences this causes, but it was the only way of keeping “Exploring ES6” from aging too quickly.

Other changes:

* New entry in the glossary: “protocol”
* Major rewrite of Sect. “The temporal dead zone” in Chap. “Variables and scoping”.

# Release 2015-12-27

* New section “Configuring which objects are spread by `concat()`” in the chapter on Arrays.
* New section “Assigning versus defining properties” in Chap. “New OOP features besides classes”
* New section “Enumerability in ECMAScript 6” in Chap. “New OOP features besides classes”
* New section “Customizing basic language operations via well-known symbols” in Chap. “New OOP features besides classes”
* New sections in Chap. “Maps and Sets”: “Arbitrary Maps as JSON via Arrays of pairs” and “String Maps as JSON via objects”
* Chap. “metaprogramming with proxies”: new section “Intercepting method calls”, various smaller improvements
* Complete rewrite of Sect. “Well-known symbols” in the chapter on symbols.
* New section “String methods that delegate regular expression work to their parameters” in the chapter on strings.

# Release 2015-12-25

* Array chapter has a new section on holes
* Removed outdated section on bundling

# Release 2015-12-19

* A lot of work went into a complete rewrite of chapter “Deploying ECMAScript 6”:
    * More type checkers and transpilers are mentioned (Closure Compiler, Flow, etc.)
    * Everything was upgraded to Babel 6.
    * I’m always using npm for build tasks (I previously used gulp in the section on deploying client-side ES6 via webpack).
* A few smaller fixes.

# Release 2015-11-25

* Fixed many errata
* New section on `__proto__` in the chapter “New OOP features besides classes”
* New chapter “About the author”

# Release 2015-10-19

* Foreword by Allen Wirfs-Brock
* Rewrite of section “Why should I read this book?” in chapter “What you need to know about this book”
* A few smaller fixes

# Release 2015-10-03

* New chapter: “Typed Arrays”
* Complete rewrite of Sect. “Methods versus callbacks” in Chap. “Callable entities in ECMAScript 6”
* I improved the following two sections (chapter “Parameter handling”):
    * ‘Referring to other parameters in default values’
    * ‘Referring to “inner” variables in default values’

# Release 2015-09-20

* New chapter: “New regular expression features”
* New chapter: “Unicode in ES6”
* New entry in the ES6 FAQ: “Isn’t ECMAScript 6 now called ECMAScript 2015?”
* A few smaller fixes and changes.

# Release 2015-09-12

* Chapter on modules: I changed much of this chapter and am now describing imports as views on exports.
    * Complete rewrite of section “Default exports (one per module)”.
    * New section: “Details: imports as views on exports”.
    * Rearranged several sections, so that information is introduced more incrementally.
    * New FAQ entries.
* Chapter on Arrays:
    * Explanation of Array.prototype.copyWithin().
    * New section “Overview” at the beginning.
* Various smaller fixes.

# Release 2015-08-15

* New chapter: “First steps with ECMAScript 6”

# Release 2015-08-04

* New chapter: “Tail call optimization”
* One additional TOC level
* Back, due to popular demand: Sect 15.5, “Constructor calls explained via JavaScript code”
* Several minor corrections and fixed typos

# Release 2015-06-28

* Moved the HTML spec links
    * From: https://people.mozilla.org/~jorendorff/es6-draft.html
    * To: http://www.ecma-international.org/ecma-262/6.0/
* Mentioned the old terminology in the template literals FAQ.
* Chapter on modules, Sect. “All exporting styles”: default exports were missing the keyword `default`.
* Removed Sect 15.5, “Constructor calls explained via JavaScript code”
* Sect. 9.1.3: Fixed the table: classes are block-scoped, `import` is module-global only.
* Chapter on classes: fixed the code of the functions `SpeciesConstructor()` and `isObject()`.
* Minor edits to make FAQ headlines more consistent
* Fixed a few minor submitted errata

# First release: 2015-06-13