es2018 support

rubys · rubys · commit afa4add8a167 · 2019-04-25T09:38:35.000-04:00
diff --git a/README.md b/README.md
@@ -236,6 +236,7 @@ the script.
     * `.last` becomes `[*.length-1]`
     * `.last(n)` becomes `.slice(*.length-1, *.length)`
     * `.max` becomes `Math.max.apply(Math)`
+    * `.merge` becomes `Object.assign({}, ...)`
     * `.merge!` becomes `Object.assign()`
     * `.min` becomes `Math.min.apply(Math)`
     * `.nil?` becomes `== null`
@@ -566,6 +567,14 @@ conversion is made by the `functions` filter:
 
 * `.each_entry` becomes `Object.entries().forEach`
 
+ES2018 support
+---
+
+When option `eslevel: 2018` is provided, the following additional
+conversion is made by the `functions` filter:
+
+* `.merge` becomes `{...a, ...b}`
+
 Picking a Ruby to JS mapping tool
 ---
 
diff --git a/demo/ruby2js.rb b/demo/ruby2js.rb
@@ -17,6 +17,7 @@
 #         --es2015 
 #         --es2016 
 #         --es2017 
+#         --es2018 
 #         --strict
 #         ---filter filter
 #         -f filter
@@ -95,15 +96,15 @@
     _input type: 'checkbox', name: 'ast', id: 'ast', checked: !!@ast
     _label 'Show AST', for: 'ast'
 
-    _input type: 'checkbox', name: 'es2017', id: 'es2017', checked: !!@es2017
-    _label 'ES2017', for: 'es2017'
+    _input type: 'checkbox', name: 'es2018', id: 'es2018', checked: !!@es2018
+    _label 'ES2018', for: 'es2018'
   end
 
   if @ruby
     _div_? do
       raise $load_error if $load_error
 
-      options[:eslevel] = 2017 if @es2017
+      options[:eslevel] = 2018 if @es2018
 
       ruby = Ruby2JS.convert(@ruby, options)
 
diff --git a/lib/ruby2js.rb b/lib/ruby2js.rb
@@ -81,6 +81,10 @@ def es2017
         @options[:eslevel] >= 2017
       end
 
+      def es2018
+        @options[:eslevel] >= 2018
+      end
+
       def process(node)
         ast, @ast = @ast, node
         replacement = super
diff --git a/lib/ruby2js/converter.rb b/lib/ruby2js/converter.rb
@@ -138,6 +138,10 @@ def es2017
       @eslevel >= 2017
     end
 
+    def es2018
+      @eslevel >= 2018
+    end
+
     @@handlers = []
     def self.handle(*types, &block)
       types.each do |type| 
diff --git a/lib/ruby2js/converter/hash.rb b/lib/ruby2js/converter/hash.rb
@@ -12,10 +12,26 @@ class Converter
 
         (singleton ? put('{') : puts('{'))
 
-        pairs.each_with_index do |node, index|
-          raise Error.new("kwsplat", @ast) if node.type == :kwsplat
-
+        index = 0
+        while pairs.length > 0
+          node = pairs.shift
           (singleton ? put(', ') : put(",#@ws")) unless index == 0
+          index += 1
+
+          if node.type == :kwsplat
+            if es2018
+              if node.children.first.type == :hash
+                pairs.unshift *node.children.first.children
+                index = 0
+              else
+                puts '...'; parse node.children.first
+              end
+
+              next
+            else
+              raise Error.new("kwsplat", @ast)
+            end
+          end
 
           if not @comments[node].empty?
             (puts ''; singleton = false) if singleton
diff --git a/lib/ruby2js/es2018.rb b/lib/ruby2js/es2018.rb
@@ -0,0 +1,5 @@
+require 'ruby2js'
+
+if Ruby2JS.eslevel_default < 2018
+  Ruby2JS.eslevel_default = 2018
+end
diff --git a/lib/ruby2js/es2018/strict.rb b/lib/ruby2js/es2018/strict.rb
@@ -0,0 +1,3 @@
+require 'ruby2js/es2018'
+
+Ruby2JS.strict_default = true
diff --git a/lib/ruby2js/filter/functions.rb b/lib/ruby2js/filter/functions.rb
@@ -35,6 +35,27 @@ def on_send(node)
         elsif method == :keys and args.length == 0 and node.is_method?
           process S(:send, s(:const, nil, :Object), :keys, target)
 
+        elsif method == :merge
+          args.unshift target
+
+          if es2015
+            if es2018
+              process S(:hash, *args.map {|arg| s(:kwsplat, arg)})
+            else
+              process S(:send, s(:const, nil, :Object), :assign, s(:hash),
+                *args)
+            end
+          else
+            copy = [s(:gvasgn, :$$, s(:hash))]
+
+            s(:send, s(:block, s(:send, nil, :lambda), s(:args),
+              s(:begin, *copy, *args.map {|modname|
+              s(:for, s(:lvasgn, :$_), modname,
+              s(:send, s(:gvar, :$$), :[]=,
+              s(:lvar, :$_), s(:send, modname, :[], s(:lvar, :$_))))
+              }, s(:return, s(:gvar, :$$)))), :[])
+          end
+
         elsif method == :merge!
           if es2015
             process S(:send, s(:const, nil, :Object), :assign, target, *args)
diff --git a/spec/es2015_spec.rb b/spec/es2015_spec.rb
@@ -179,6 +179,10 @@ def to_js_fn(string)
       to_js( 'a=1; {a:a}' ).must_equal 'let a = 1; {a}'
     end
 
+    it "should handle merge" do
+      to_js_fn( 'a.merge(b)' ).must_equal 'Object.assign({}, a, b)'
+    end
+
     it "should handle merge!" do
       to_js_fn( 'a.merge!(b)' ).must_equal 'Object.assign(a, b)'
     end
diff --git a/spec/es2018_spec.rb b/spec/es2018_spec.rb
@@ -0,0 +1,17 @@
+gem 'minitest'
+require 'minitest/autorun'
+
+describe "ES2018 support" do
+  
+  def to_js_fn(string)
+    Ruby2JS.convert(string, eslevel: 2018,
+      filters: [Ruby2JS::Filter::Functions]).to_s
+  end
+  
+  describe :Hash_Spread do
+    it "should convert merge to Object spread" do
+      to_js_fn( 'a.merge(b)' ).must_equal '{...a, ...b}'
+      to_js_fn( 'a.merge(b: 1)' ).must_equal '{...a, b: 1}'
+    end
+  end
+end

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,3 @@`
	`1`	`+require 'ruby2js/es2018'`
	`2`	`+`
	`3`	`+Ruby2JS.strict_default = true`