Try improve printing

Author: nojaf

compiler/syntax/src/res_printer.ml

@@ -4404,11 +4404,16 @@ and print_jsx_expression ~state lident args cmt_tbl =
 and print_jsx_fragment ~state (children : Parsetree.expression list) cmt_tbl =
   let opening = Doc.text "<>" in
   let closing = Doc.text "</>" in
-  let line_sep = if List.length children > 0 then Doc.hard_line else Doc.line in
+  let line_sep =
+    if
+      List.length children > 0
+      || List.exists ParsetreeViewer.is_jsx_expression children
+    then Doc.hard_line
+    else Doc.line
+  in
   Doc.group
     (Doc.concat
        [
-         line_sep;
          opening;
          (match children with
          | [] -> Doc.nil
@@ -4418,9 +4423,9 @@ and print_jsx_fragment ~state (children : Parsetree.expression list) cmt_tbl =
                 [
                   Doc.line;
                   Doc.join ~sep:line_sep
-                    (List.map
-                       (fun e ->
-                         print_jsx_child ~spread:false ~state e ~cmt_tbl)
+                       (List.map
+                          (fun e ->
+                            print_jsx_child ~spread:false ~state e ~cmt_tbl)
                        children);
                 ]));
          line_sep;

tests/syntax_tests/data/conversion/reason/expected/string.res.txt

@@ -8,7 +8,6 @@ carriage return`
 let x = "\""
 let y = "\n"
 
-
 <>
   {"\n"->React.string}
 </>

tests/syntax_tests/data/printer/comments/expected/jsx.res.txt

@@ -65,8 +65,7 @@ module Cite = {
   React.string("Hello, World!")}
 </div>
 
-let x =
-<>
+let x = <>
   {a}
   {b}
 </>

tests/syntax_tests/data/printer/expr/expected/braced.res.txt

@@ -318,11 +318,9 @@ let x = {
 }
 
 // string constant should be printed correct
-
 <>
   {"\n"->React.string}
 </>
-
 <>
   {"\""->React.string}
 </>

tests/syntax_tests/data/printer/expr/expected/callback.res.txt

@@ -202,7 +202,6 @@ let f = () => {
     | Loading => "Loading ..."->React.string
     | Done(Error(_)) => "Error"->React.string
     | Done(Ok(users)) =>
-
       <>
         <ul>
           {users

tests/syntax_tests/data/printer/expr/expected/jsx.res.txt

@@ -99,8 +99,7 @@ let nav3 =
     </NavContent>
   </Nav>
 
-let avatarSection =
-<>
+let avatarSection = <>
   <div style={{"zIndex": "1", "opacity": opacityUser}}>
     <Avatar user={user} size={45} />
   </div>
@@ -122,7 +121,7 @@ let avatarSection =
     : React.nullElement}
 </>
 
-let x =  <> </>
+let x = <> </>
 
 let x =
   <div
@@ -315,7 +314,6 @@ let x = <MyComponent sidebar={<div> test </div>} nav={<Navbar />} />
 module App = {
   @react.component
   let make = () => {
-
     <>
       1
     </>
@@ -325,7 +323,6 @@ module App = {
 module App = {
   @react.component
   let make = () => {
-
     <>
       <div />
     </>
@@ -439,8 +436,7 @@ let x = <C> ...{() => msg->React.string} </C>
 
 let x = <C> ...{array->Array.map(React.string)} </C>
 
-let x =
-<>
+let x = <>
   {array->Array.map(React.string)}
 </>
 
@@ -455,8 +451,7 @@ let x = {
 }
 
 let x = {
-  let _ =
-  <>
+  let _ = <>
     {children}
   </>
   msg->React.string

tests/syntax_tests/data/printer/expr/expected/switch.res.txt

@@ -49,7 +49,6 @@ switch route {
     <div> {React.string("Second A div")} </div>
   </div>
 | B =>
-
   <>
     <div> {React.string("First B div")} </div>
     <div> {React.string("Second B div")} </div>