Highlights

Hash is now bridged to JavaScript Map

This change brings a lot of benefits, but also some incompatibilities. The main benefit is that Hash now is both more performant and relies on native JavaScript capabilities.
This improves interoperability with JavaScript. As a downside, applications reaching for internal Hash data structures will need to be updated.

Interacting with Hash from JavaScript is easier than ever:

hash = `new Map([['a', 1], ['b', 2]])`
hash # => {a: 1, b: 2}
`console.log(hash)` # => Map(2) {"a" => 1, "b" => 2}
`hash.get('a')` # => 1
`hash.set('c', 3)`
hash # => {a: 1, b: 2, c: 3}
hash.keys # => ["a", "b", "c"]
hash.values # => [1, 2, 3]

Performance improvements

This release brings a lot of performance improvements, our tests on Asciidoctor show a 25% improvement in performance, but we've seen up to 66% performance improvement on some applications.

Changelog

Deprecated

• Deprecate using x-string to access JavaScript without an explicit magic-comment (#2543)

Compatibility

• Add a magic-comment that will disable x-string compilation to JavaScript (#2543)
• Pass value in PromiseV2#always just like PromiseV1#always does it (#2579)
• #hash now returns integers (#2582)
• Improve Range#include?/member?/cover?/=== (#2598)
• Make Module#define_method more compatible with CRuby (#2593)
• Hash#clone must freeze clone if original is frozen, but Hash#dup must not (#2603)

Fixed

• Fix Kernel#Float with exception: option (#2532)
• Fix Kernel#Integer with exception: option (#2531)
• Fix String#split with limit and capturing regexp (#2544)
• Fix switch with Object-wrapped values (#2542)
• Fix non-direct subclasses of bridged classes not calling the original constructor (#2546)
• Regexp.escape: Cast to String or drop exception (#2552)
• Propagate removal of method from included/prepended modules (#2553)
• Restore nodejs/yaml functionality (#2551)
• Fix sine Range#size edge cases (#2541)
• Use a Map instead of a POJO for the jsid_cache (#2584)
• Fix String#object_id, String#__id__, String#hash to match CRuby's behavior (#2576)
• Lowercase response headers in SimpleServer for rack 3.0 compatibility (#2578)
• Fix Module#clone and Module#dup to properly copy methods (#2572)
• Chrome runner fix: support code that contains </script> (#2581)
• Do not skip $truthy when left hand side of a comparison is self (#2596)
• Unexpected return/break should raise LocalJumpError (#2591)

Added

• SourceMap support for Kernel#eval (#2534)
• Add CGI::Util#escapeURIComponent and CGI::Util#unescapeURIComponent (#2566)
• CGI::Util implement additional methods (#2601)

Changed

• Change compilation of Regexp nodes that may contain advanced features, so if invalid that they would raise at runtime, not parse-time (#2548)
• Hash is now bridged to JavaScript Map and support for non-symbol keys in keyword arguments (#2568)

Documentation

• Bridging documentation (#2541)
• Fix Typo in Running tests Section of README.md File (#2580)

Performance

• Improve performance of Array#intersect? and #intersection (#2533)
• Proc#call: Refactor for performance (#2541)
• Opal.stub_for: optimize (#2541)
• Hash: Optimize #to_a (#2541)
• Array: Optimize #collect/#map (#2541)
• Optimize argument slicing in runtime for performance (#2555)
• Closure: Generate a JavaScript object, not an Error, gain up to 15% on Asciidoctor (#2556)
• Optimize String#split and String#start_with (#2560)
• Compute $@ dynamically (#2592)
• Optimize the $prop helper (#2597)
• Improve Array.push() performance when pushing many items (#2565)
• Optimize Opal.instance_methods (#2600)

Internal

• Update rubocop (#2535)
• Match3Node Cleanup (#2541)
• IFlipFlop/EFlipFlop: Refactor for readability (#2541)
• ForRewriter: Refactor for readability (#2541)