only pass buffer files to sourcemaps

Author: Contra

lib/dest/index.js

@@ -3,9 +3,14 @@
 var through2 = require('through2');
 var sourcemaps = require('gulp-sourcemaps');
 var duplexify = require('duplexify');
+var ternaryStream = require('ternary-stream');
 var prepareWrite = require('../prepareWrite');
 var writeContents = require('./writeContents');
 
+function canSourceMap(file) {
+  return file.isBuffer();
+}
+
 function dest(outFolder, opt) {
   if (!opt) {
     opt = {};
@@ -20,7 +25,7 @@ function dest(outFolder, opt) {
     });
   }
 
-  var mapStream = sourcemaps.write(opt.sourcemaps);
+  var mapStream = ternaryStream(canSourceMap, sourcemaps.write(opt.sourcemaps));
   var saveStream = through2.obj(saveFile);
   var outputStream = duplexify.obj(mapStream, saveStream);
   mapStream.pipe(saveStream);

package.json

@@ -21,6 +21,7 @@
     "object-assign": "^4.0.0",
     "strip-bom": "^2.0.0",
     "strip-bom-stream": "^1.0.0",
+    "ternary-stream": "^1.2.3",
     "through2": "^2.0.0",
     "through2-filter": "^2.0.0",
     "vinyl": "^1.0.0"