Only write flags when they evaluate to true.

test/write.js

@@ -16,6 +16,20 @@ function assertHasLine(str, line) {
     assert(found, 'Could not find line: ' + line);
 }
 
+function assertDoesntHaveLine(str, line) {
+    var lines = str.split('\n');
+    var found = false;
+
+    for (var i = 0; i < lines.length; i++) {
+        if (lines[i].trim() === line) {
+            found = true;
+            break;
+        }
+    }
+
+    assert(!found, 'Shouldn\'t have line: ' + line);
+}
+
 describe('Write', function () {
     it('write flags', function () {
         var input = fs.readFileSync(__dirname + '/fixtures/fuzzy.po', 'utf8');
@@ -24,6 +38,17 @@ describe('Write', function () {
         assertHasLine(str, '#, fuzzy');
     });
 
+    it('write flags only when true', function () {
+        var input = fs.readFileSync(__dirname + '/fixtures/fuzzy.po', 'utf8');
+        var po = PO.parse(input);
+
+        // Flip flag
+        po.items[0].flags.fuzzy = false;
+
+        var str = po.toString();
+        assertDoesntHaveLine(str, '#, fuzzy');
+    });
+
     it('write msgid', function () {
         var input = fs.readFileSync(__dirname + '/fixtures/fuzzy.po', 'utf8');
         var po = PO.parse(input);