Break long exports into multiple lines.

Ref #19.

src/printer.js

@@ -1866,9 +1866,25 @@ function printExportDeclaration(path, options, print) {
     } else {
       parts.push(
         decl.exportKind === "type" ? "type " : "",
-        shouldPrintSpaces ? "{ " : "{",
-        join(", ", path.map(print, "specifiers")),
-        shouldPrintSpaces ? " }" : "}"
+        conditionalGroup([
+          concat([
+            shouldPrintSpaces ? "{ " : "{",
+            join(", ", path.map(print, "specifiers")),
+            shouldPrintSpaces ? " }" : "}"
+          ]),
+          concat([
+            "{",
+            indent(
+              options.tabWidth,
+              concat([
+                hardline,
+                join(concat([",", hardline]), path.map(print, "specifiers"))
+              ])
+            ),
+            hardline,
+            "}"
+          ])
+        ])
       );
     }
 

tests/declare_export/__snapshots__/jsfmt.spec.js.snap

@@ -352,8 +352,15 @@ declare export {
  * @flow
  */
 
+<<<<<<< bbe2524dab164d43febc1a8d549a76e26eb9d483
 declare export { numberValue1, numberValue2 as numberValue2_renamed } from \"ES6_ExportFrom_Source1\";
 "
+=======
+declare export {
+  numberValue1,
+  numberValue2 as numberValue2_renamed
+} from \"ES6_ExportFrom_Source1\";"
+>>>>>>> Break long `exports` into multiple lines.
 `;
 
 exports[`test ES6_ExportFrom_Intermediary2.js 1`] = `
@@ -372,8 +379,15 @@ declare export {
  * @flow
  */
 
+<<<<<<< bbe2524dab164d43febc1a8d549a76e26eb9d483
 declare export { numberValue1, numberValue2 as numberValue2_renamed2 } from \"ES6_ExportFrom_Source2\";
 "
+=======
+declare export {
+  numberValue1,
+  numberValue2 as numberValue2_renamed2
+} from \"ES6_ExportFrom_Source2\";"
+>>>>>>> Break long `exports` into multiple lines.
 `;
 
 exports[`test ES6_ExportFrom_Source1.js 1`] = `

tests/es6modules/__snapshots__/jsfmt.spec.js.snap

@@ -429,8 +429,15 @@ export {
  * @flow
  */
 
+<<<<<<< bbe2524dab164d43febc1a8d549a76e26eb9d483
 export { numberValue1, numberValue2 as numberValue2_renamed } from \"ES6_ExportFrom_Source1\";
 "
+=======
+export {
+  numberValue1,
+  numberValue2 as numberValue2_renamed
+} from \"ES6_ExportFrom_Source1\";"
+>>>>>>> Break long `exports` into multiple lines.
 `;
 
 exports[`test ES6_ExportFrom_Intermediary2.js 1`] = `
@@ -449,8 +456,15 @@ export {
  * @flow
  */
 
+<<<<<<< bbe2524dab164d43febc1a8d549a76e26eb9d483
 export { numberValue1, numberValue2 as numberValue2_renamed2 } from \"ES6_ExportFrom_Source2\";
 "
+=======
+export {
+  numberValue1,
+  numberValue2 as numberValue2_renamed2
+} from \"ES6_ExportFrom_Source2\";"
+>>>>>>> Break long `exports` into multiple lines.
 `;
 
 exports[`test ES6_ExportFrom_Source1.js 1`] = `

tests/prettier/__snapshots__/jsfmt.spec.js.snap

@@ -1,3 +1,4 @@
+<<<<<<< bbe2524dab164d43febc1a8d549a76e26eb9d483
 exports[`test directives.js 1`] = `
 "\"use strict\";
 
@@ -11,6 +12,18 @@ function fn() {
   \"use strict\";
 }
 "
+=======
+exports[`test exports.js 1`] = `
+"export { value1, value2 as value2_renamed, value3, value4 as value4_renamed, value5 } from \"exports\";
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+export {
+  value1,
+  value2 as value2_renamed,
+  value3,
+  value4 as value4_renamed,
+  value5
+} from \"exports\";"
+>>>>>>> Break long `exports` into multiple lines.
 `;
 
 exports[`test optional-type-name.js 1`] = `

tests/prettier/exports.js

@@ -0,0 +1 @@
+export { value1, value2 as value2_renamed, value3, value4 as value4_renamed, value5 } from "exports";