Version 1.47.90
---------------

- New JavaScript features! This version of GJS is based on SpiderMonkey 38, an
  upgrade from the previous ESR (Extended Support Release) of SpiderMonkey 31.
  Our plans are to continue upgrading to subsequent ESRs as maintainer
  availability allows. Here are the highlights of the new JavaScript features.
  For more information, look them up on MDN or devdocs.io.

  * New syntax
    + Shorthand syntax for method definitions: { foo() { return 5; } }
    + Shorthand syntax for object literals: let b = 42; let o = {b}; o.b === 42
    + Computed property names for the above, as well as in getter and setter
      expressions and destructuring assignment: { ['b' + 'ar']() { return 6; } }
    + Spread operator in destructuring assignment: let [a, ...b] = [1, 2, 3];
    + Template literals: `Hello, ${name}` with optional tags: tag`string`

  * New APIs
    + Symbol, a new fundamental type
    + WeakSet, a Set which does not prevent its members from being
      garbage-collected
    + [Symbol.iterator] properties for Array, Map, Set, String, TypedArray, and
      the arguments object
    + New Array and TypedArray functionality: Array.copyWithin(), Array.from()
    + New return() method for generators
    + New Number.isSafeInteger() method
    + New Object.assign() method which can replace Lang.copyProperties() in many
      cases
    + New Object.getOwnPropertySymbols() method
    + New RegExp flags, global, ignoreCase, multiline, sticky properties that
      give access to the flags that the regular expression was created with
    + String.raw, a tag for template strings similar to Python's r""
    + New TypedArray methods for correspondence with Array: entries(), every(),
      fill(), filter(), find(), findIndex(), forEach(), indexOf(), join(),
      keys(), lastIndexOf(), map(), of(), reduce(), reduceRight(), reverse(),
      slice(), some(), values()

  * New behaviour
    + Temporal dead zone: print(x); let x = 5; no longer allowed
    + Full ES6-compliant implementation of const keyword
    + The Set, Map, and WeakMap constructors can now take null as their argument
    + The WeakMap constructor can now take an iterable as its argument
    + The Function.name and Function.length properties are configurable
    + When subclassing Map, WeakMap, and Set or using the constructors on
      generic objects, they will look for custom set() and add() methods.
    + RegExp.source and RegExp.toString() now deal with empty regexes, and
      escape their output.
    + Non-object arguments to Object.preventExtensions() now do not throw an
      exception, simply return the original object

  * Backwards-incompatible changes
    + It is now a syntax error to declare the same variable twice with "let" or
      "const" in the same scope. Existing code may need to be fixed, but the
      fix is trivial.
    + SpiderMonkey is now extra vocal about warning when you access an
      undefined property, and this causes some false positives. You can turn
      this warning off by setting GJS_DISABLE_EXTRA_WARNINGS=1. If it is overly
      annoying, let me know and I will consider making it disabled by default
      in a future release.
    + When enumerating the importer object (i.e.,
      "for (let i in imports) {...}") you will now get the names of any built-in
      modules that have previously been imported. (But don't do this, anyway.)

- Closed bugs:

  * SpiderMonkey 38 prep [#776966, Philip Chimento]
  * Misc fixes [#777205, Philip Chimento]
  * missing class name in error message [#642506, Philip Chimento]
  * Add continuous integration to GJS [#776549, Claudio André]
  * Switch to SpiderMonkey 38 [#777962, Philip Chimento]

- Progress towards a build of GJS on Windows [Chun-wei Fan]
- Progress towards increasing test coverage [Claudio André]
- Misc bug fixes [Philip Chimento]