Filter out node_modules as early as possible

lib/tree.js

@@ -49,9 +49,7 @@ class Tree {
  requireConfig: this.config.requireConfig,
  webpackConfig: this.config.webpackConfig,
  visited: visited,
- filter: (path) => {
- return this.config.includeNpm || path.indexOf('node_modules') < 0;
- }
+ filter: this.filterPath.bind(this)
  }));
  });
 
@@ -66,6 +64,15 @@ class Tree {
  return tree;
  }
 
+ /**
+ * Filter out some paths from found files
+ * @param {String} path
+ * @return {Boolean}
+ */
+ filterPath(path) {
+ return this.config.includeNpm || path.indexOf('node_modules') < 0;
+ }
+
  /**
  * Get directories from the source paths
  * @return {Promise} resolved with an array of directories
@@ -97,7 +104,7 @@ class Tree {
  }
 
  walk.sync(srcPath, (filePath, stat) => {
- if (!stat.isFile()) {
+ if (!this.filterPath(filePath) || !stat.isFile()) {
  return;
  }