Fix jashkenas#4290 definitively, with improved output for arrays with interspersed block comments

Author: GeoffreyBooth

lib/coffeescript/nodes.js

@@ -1458,13 +1458,23 @@ exports.Arr = class Arr extends Base
 
     compiledObjs = (obj.compileToFragments o, LEVEL_LIST for obj in @objects)
     for fragments, index in compiledObjs
-      if index
+      for fragment in fragments when fragment.type is 'HereComment'
+        fragment.code = fragment.code.trim()
+      if index isnt 0
         answer.push @makeCode ", "
       answer.push fragments...
-    if fragmentsToText(answer).indexOf('\n') >= 0
-      answer.unshift @makeCode "[\n#{o.indent}"
+    if '\n' in fragmentsToText(answer)
+      for fragment, fragmentIndex in answer
+        if fragment.type is 'HereComment'
+          fragment.code = "#{multident(fragment.code, o.indent)}\n#{o.indent}"
+          fragment.code = "\n#{fragment.code}" unless fragmentIndex is 0
+        else if fragment.code is ', '
+          fragment.code = ','
+      answer.unshift @makeCode "[\n#{unless answer[0].type is 'HereComment' then o.indent else ''}"
       answer.push @makeCode "\n#{@tab}]"
     else
+      for fragment in answer when fragment.type is 'HereComment'
+        fragment.code = "#{fragment.code} "
       answer.unshift @makeCode '['
       answer.push @makeCode ']'
     answer

src/nodes.coffee

@@ -403,6 +403,82 @@ test "#4290: Block comments in array literals", ->
   ]
   arrayEq arr, [3, 42]
 
+test "Block comments in array literals are properly indented 1", ->
+  eqJS '''
+  arr = [
+    ### ! ###
+    3
+    42
+  ]''', '''
+  var arr;
+
+  arr = [/* ! */ 3, 42];'''
+
+test "Block comments in array literals are properly indented 2", ->
+  eqJS '''
+  arr = [
+    ###  ###
+    3
+    ###
+      What is the meaning of life, the universe, and everything?
+    ###
+    42
+  ]''', '''
+  var arr;
+
+  arr = [
+    /*  */
+    3,
+    /*
+      What is the meaning of life, the universe, and everything?
+    */
+    42
+  ];'''
+
+test "Block comments in array literals are properly indented 3", ->
+  eqJS '''
+  arr = [
+    ###
+      How many stooges are there?
+    ###
+    3
+    ### Who’s on first? ###
+    'Who'
+  ]''', '''
+  var arr;
+
+  arr = [
+    /*
+      How many stooges are there?
+    */
+    3,
+    /* Who’s on first? */
+    'Who'
+  ];'''
+
+test "Block comments in array literals are properly indented 4", ->
+  eqJS '''
+  arr = [
+    1
+    ###
+      How many stooges are there?
+    ###
+    3
+    ### Who’s on first? ###
+    'Who'
+  ]''', '''
+  var arr;
+
+  arr = [
+    1,
+    /*
+      How many stooges are there?
+    */
+    3,
+    /* Who’s on first? */
+    'Who'
+  ];'''
+
 test "Line comments are properly indented", ->
   eqJS '''
   # Unindented comment