Announcing Scala.js 1.16.0.

_config.yml

@@ -64,7 +64,7 @@ colors:  #in hex code if not noted else
 
 ### VERSIONS ###
 versions:
-  scalaJS: 1.15.0
+  scalaJS: 1.16.0
   scalaJSBinary: 1
   scalaJS06x: 0.6.33
   scalaJS06xBinary: 0.6

_data/library/versions.yml

@@ -32,3 +32,4 @@
 - 1.11.0
 - 1.12.0
 - 1.13.0
+- 1.16.0

_posts/news/2024-03-19-announcing-scalajs-1.16.0.md

@@ -0,0 +1,105 @@
+---
+layout: post
+title: Announcing Scala.js 1.16.0
+category: news
+tags: [releases]
+permalink: /news/2024/03/19/announcing-scalajs-1.16.0/
+---
+
+
+We are excited to announce the release of Scala.js 1.16.0!
+
+The biggest highlight of this release is that we added a Scala.js-specific minifier.
+When combined with a general-purpose JavaScript minifier, our minifier should bring most of the code size benefits of the Google Closure Compiler when the latter cannot be enabled, notably when emitting ECMAScript modules.
+
+Scala.js 1.16.0 also upgrades by default to the standard library of Scala 2.12.19 and 2.13.13.
+
+Read on for more details.
+
+<!--more-->
+
+## Getting started
+
+If you are new to Scala.js, head over to [the tutorial]({{ BASE_PATH }}/tutorial/).
+
+If you need help with anything related to Scala.js, you may find our community [in `#scala-js` on Discord](https://discord.com/invite/scala) and [on Stack Overflow](https://stackoverflow.com/questions/tagged/scala.js).
+
+Bug reports can be filed [on GitHub](https://github.com/scala-js/scala-js/issues).
+
+## Release notes
+
+If upgrading from Scala.js 0.6.x, make sure to read [the release notes of Scala.js 1.0.0]({{ BASE_PATH }}/news/2020/02/25/announcing-scalajs-1.0.0/) first, as they contain a host of important information, including breaking changes.
+
+This is a **minor** release:
+
+* It is backward binary compatible with all earlier versions in the 1.x series: libraries compiled with 1.0.x through 1.15.x can be used with 1.16.0 without change.
+* It is *not* forward binary compatible with 1.15.x: libraries compiled with 1.16.0 cannot be used with 1.15.x or earlier.
+* It is *not* entirely backward source compatible: it is not guaranteed that a codebase will compile *as is* when upgrading from 1.15.x (in particular in the presence of `-Xfatal-warnings`).
+
+As a reminder, libraries compiled with 0.6.x cannot be used with Scala.js 1.x; they must be republished with 1.x first.
+
+## Enhancements with compatibility concerns
+
+### Changes to the IR and linker APIs
+
+For tooling authors who directly manipulate the IR and linker APIs, there have been some breaking changes in that area.
+This is in line with our version policy for the linker APIs.
+
+The most likely changes you may hit are:
+
+* `FieldName` is now a composite of the defining `ClassName` and a `SimpleFieldName`.
+* `StoreModule` has no parameter anymore; it implicitly applies to storing the `this` value of the enclosing module class.
+
+## Enhancements
+
+### Scala.js-specific minifier
+
+In the `fullLink` mode, the Scala.js linker now includes dedicated code size optimizations.
+They are mostly useful when the Google Closure Compiler is deactivated, which is the case by default when emitting ECMAScript modules.
+
+The most important optimization is that it compresses all *property* names (fields and methods) of Scala classes.
+It computes how frequently each one is used across the codebase, and assigns shorter names to the most frequent ones.
+
+Renaming local and global variables and functions in this way is a standard feature of general-purpose JavaScript minifiers.
+However, in general they cannot rename *properties* without breaking the semantics of JavaScript programs.
+This is why Scala.js has leveraged Closure since the very first relase.
+Closure's so-called "advanced optimizations" assume that the JavaScript program fits in a specific subset of semantics, which allows it to rename properties.
+
+Unfortunately, the way Closure handles ES modules is incompatible with what we need.
+Closure is therefore disabled when emitting ES modules from Scala.js.
+This has resulted in large bundle sizes for users of ES modules.
+
+Our minifier, which is aware of our types and of Scala.js semantics, fills that gap between Closure and general-purpose minifiers.
+When combined with a general-purpose minifier such as the one bundled with Vite, the new optimizations bring code size around 15% bigger than Closure.
+Contrast that with the previous status quo, which was several *times* bigger than the Closure output.
+
+If, for some reason, the new optimizations cause issues in your case, you can disable them with
+
+{% highlight scala %}
+scalaJSLinkerConfig ~= { _.withMinify(false) }
+{% endhighlight %}
+
+Please let us know if you encounter any issue with this new mode.
+
+### Other code size improvements
+
+In addition to the minifier, Scala.js 1.16.0 generally produces smaller .js files.
+This is the result of various code size optimizations that we apply in all configurations.
+
+In particular, the optimizer now eagerly "dealiases" `val` fields of top-level objects if they are simple and if the object's initializer can be proven to be pure.
+
+### Reduced memory consumption of the linker
+
+The linker is generally optimized for *incremental* runs, which naturally requires to maintain a lot of caches in memory.
+We have started work on reducing the memory consumption of the linker without compromising on speed.
+This release already ships with the first installment of these improvements, reducing the memory footprint of the linker by 10%.
+If interested, you can find out the details [in the relevant pull request #4917](https://github.com/scala-js/scala-js/pull/4917).
+
+## Bug fixes
+
+Among others, the following bugs have been fixed in 1.16.0:
+
+* [#4929](https://github.com/scala-js/scala-js/issues/4929) Assertion failed: Trying to move a local VarDef after the super constructor call of a non-native JS class
+* [#4949](https://github.com/scala-js/scala-js/issues/4949) Wrong pretty-printing of JS tree that *starts* with an object lit
+
+You can find the full list [on GitHub](https://github.com/scala-js/scala-js/issues?q=is%3Aissue+milestone%3Av1.16.0+is%3Aclosed).

doc/all-api.md

@@ -5,6 +5,16 @@ title: All previous versions of the Scala.js API
 
 ## All previous versions of the API
 
+### Scala.js 1.16.0
+* [1.16.0 scalajs-library]({{ site.production_url }}/api/scalajs-library/1.16.0/scala/scalajs/js/index.html)
+* [1.16.0 scalajs-test-interface]({{ site.production_url }}/api/scalajs-test-interface/1.16.0/)
+* [1.16.0 scalajs-javalib-intf]({{ site.production_url }}/api/scalajs-javalib-intf/1.16.0/)
+* [1.16.0 scalajs-ir]({{ site.production_url }}/api/scalajs-ir/1.16.0/org/scalajs/ir/index.html)
+* [1.16.0 scalajs-linker-interface]({{ site.production_url }}/api/scalajs-linker-interface/1.16.0/org/scalajs/linker/interface/index.html) ([Scala.js version]({{ site.production_url }}/api/scalajs-linker-interface-js/1.16.0/org/scalajs/linker/interface/index.html))
+* [1.16.0 scalajs-linker]({{ site.production_url }}/api/scalajs-linker/1.16.0/org/scalajs/linker/index.html) ([Scala.js version]({{ site.production_url }}/api/scalajs-linker-js/1.16.0/org/scalajs/linker/index.html))
+* [1.16.0 scalajs-test-adapter]({{ site.production_url }}/api/scalajs-sbt-test-adapter/1.16.0/org/scalajs/testing/adapter/index.html)
+* [1.16.0 sbt-scalajs]({{ site.production_url }}/api/sbt-scalajs/1.16.0/#org.scalajs.sbtplugin.package)
+
 ### Scala.js 1.15.0
 * [1.15.0 scalajs-library]({{ site.production_url }}/api/scalajs-library/1.15.0/scala/scalajs/js/index.html)
 * [1.15.0 scalajs-test-interface]({{ site.production_url }}/api/scalajs-test-interface/1.15.0/)

doc/internals/version-history.md

@@ -5,6 +5,7 @@ title: Version history
 
 ## Version history of Scala.js
 
+- [1.16.0](/news/2024/03/19/announcing-scalajs-1.16.0/)
 - [1.15.0](/news/2023/12/29/announcing-scalajs-1.15.0/)
 - [1.14.0](/news/2023/09/25/announcing-scalajs-1.14.0/)
 - [1.13.2](/news/2023/06/23/announcing-scalajs-1.13.2/)