Preserve newlines on either side of ++ and --

This closes #56 and openes the new less severe case of #203.
beautifier · Mar 25, 2013 · d5ec851 · d5ec851
1 parent bc80349
commit d5ec851
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Showing 2 changed files with 18 additions and 2 deletions.
diff --git a/beautify.js b/beautify.js
@@ -1000,8 +1000,9 @@
             if (start_of_statement()) {
                 // The conditional starts the statement if appropriate.
             } else if (wanted_newline && !is_expression(flags.mode) &&
-                last_type !== 'TK_OPERATOR' && last_type !== 'TK_EQUALS' && (
-                opt.preserve_newlines || flags.last_text !== 'var')) {
+                (last_type !== 'TK_OPERATOR' || (flags.last_text === '--' || flags.last_text === '++')) &&
+                last_type !== 'TK_EQUALS' &&
+                (opt.preserve_newlines || flags.last_text !== 'var')) {
 
                 print_newline();
             }
@@ -1291,6 +1292,12 @@
                 return;
             }
 
+            // http://www.ecma-international.org/ecma-262/5.1/#sec-7.9.1
+            // if there is a newline between -- or ++ and anything else we should preserve it.
+            if (wanted_newline && (token_text === '--' || token_text === '++')) {
+                print_newline();
+            }
+
             if (in_array(token_text, ['--', '++', '!']) || (in_array(token_text, ['-', '+']) && (in_array(last_type, ['TK_START_BLOCK', 'TK_START_EXPR', 'TK_EQUALS', 'TK_OPERATOR']) || in_array (flags.last_text, line_starters) || flags.last_text === ','))) {
                 // unary operators (and binary +/- pretending to be unary) special cases
 
@@ -1302,6 +1309,7 @@
                     //        ^^^
                     space_before = true;
                 }
+
                 if (last_type === 'TK_WORD' && in_array (flags.last_text, line_starters)) {
                     space_before = true;
                 }

diff --git a/tests/beautify-tests.js b/tests/beautify-tests.js
@@ -269,6 +269,14 @@ function run_beautifier_tests(test_obj, Urlencoded, js_beautify)
         bt('{--bar;}', '{\n    --bar;\n}');
         bt('{++bar;}', '{\n    ++bar;\n}');
 
+        // Handling of newlines around unary ++ and -- operators
+        bt('{foo\n++bar;}', '{\n    foo\n    ++bar;\n}');
+        bt('{foo++\nbar;}', '{\n    foo++\n    bar;\n}');
+
+        // This is invalid, but harder to guard against. Issue #203.
+        bt('{foo\n++\nbar;}', '{\n    foo\n    ++\n    bar;\n}');
+
+
         // regexps
         bt('a(/abc\\/\\/def/);b()', "a(/abc\\/\\/def/);\nb()");
         bt('a(/a[b\\[\\]c]d/);b()', "a(/a[b\\[\\]c]d/);\nb()");