[gjs/wip/ptomato/mozjs52: 23/37] docs: Overview of SpiderMonkey 45 features in NEWS
- From: Philip Chimento <pchimento src gnome org>
- To: commits-list gnome org
- Cc:
- Subject: [gjs/wip/ptomato/mozjs52: 23/37] docs: Overview of SpiderMonkey 45 features in NEWS
- Date: Sun, 25 Jun 2017 06:56:12 +0000 (UTC)
commit ccabefe5484c00725e52738fb98def00ae31804e
Author: Philip Chimento <philip chimento gmail com>
Date: Sun Jun 18 14:28:53 2017 -0700
docs: Overview of SpiderMonkey 45 features in NEWS
Distilled from Mozilla's documentation.
NEWS | 52 ++++++++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 52 insertions(+), 0 deletions(-)
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diff --git a/NEWS b/NEWS
index 6feab5f..306bd76 100644
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+++ b/NEWS
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+NEXT
+----
+
+- New JavaScript features! This version of GJS is based on SpiderMonkey 45, an
+ upgrade from the previous ESR (Extended Support Release) of SpiderMonkey 38.
+ 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 language features
+ + ES6 classes
+ + Reflect - built-in object with methods for interceptable operations
+
+ * New syntax
+ + Variable-length Unicode code point escapes: `"\u{1f369}"`
+ + Destructured default arguments: `function f([x, y]=[1, 2], {z: z}={z: 3})`
+ + `new.target` allows a constructor access to the original constructor that
+ was invoked
+
+ * New APIs
+ + New Array, String, and TypedArray method: includes()
+ + [Symbol.toPrimitive] property specifying how to convert an object to a
+ primitive value
+ + [Symbol.species] property allowing to override the default constructor
+ for objects
+ + [Symbol.match] property allowing to customize matching behaviour in RegExp
+ subclasses
+ + Date.toString() and RegExp.toString() generic methods
+
+ * New behaviour
+ + Date.prototype, WeakMap.prototype, and WeakSet.prototype are now ordinary
+ objects, not instances
+ + Full ES6-compliant implementation of let keyword
+ + RegExp.sticky ('y' flag) behaviour is ES6 standard, it used to be subject
+ to a long-standing bug in Firefox
+ + RegExp constructor with RegExp first argument and flags no longer throws
+ an exception (`new RegExp(/ab+c/, 'i')` works now)
+ + Generators are no longer constructible, as per ES6 (`function* f {}`
+ followed by `new f` will not work)
+ + It is now required to construct ArrayBuffer, TypedArray, Map, Set, and
+ WeakMap with the new operator
+
+ * Backwards-incompatible changes
+ + Non-standard "let expressions" and "let blocks" (e.g.,
+ `let (x = 5) { use(x) }`) are not supported any longer
+ + Variables declared with let and const are now 'global lexical bindings',
+ as per the ES6 standard, meaning that they will not be exported in
+ modules. If you cannot find symbols in your imported modules after the
+ upgrade, then likely you need to change "let" or "const" to "var" inside
+ your module file. For more information, read
+ https://blog.mozilla.org/addons/2015/10/14/breaking-changes-let-const-firefox-nightly-44/
+
Version 1.49.3
--------------
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