Merge pull request #690 from bmathews/pr/685

Add debouncing to readdirp call

Author: es128

lib/nodefs-handler.js

@@ -4,6 +4,7 @@ var fs = require('fs');
 var sysPath = require('path');
 var readdirp = require('readdirp');
 var isBinaryPath = require('is-binary-path');
+var debounce = require('lodash.debounce');
 
 // fs.watch helpers
 
@@ -341,15 +342,12 @@ function(dir, stats, initialAdd, depth, target, wh, callback) {
   parentDir.add(sysPath.basename(dir));
   this._getWatchedDir(dir);
 
+  var debouncedRead;
+
   var read = function(directory, initialAdd, done) {
     // Normalize the directory name on Windows
     directory = sysPath.join(directory, '');
 
-    if (!wh.hasGlob) {
-      var throttler = this._throttle('readdir', directory, 1000);
-      if (!throttler) return;
-    }
-
     var previous = this._getWatchedDir(wh.path);
     var current = [];
 
@@ -380,9 +378,11 @@ function(dir, stats, initialAdd, depth, target, wh, callback) {
         this._addToNodeFs(path, initialAdd, wh, depth + 1);
       }
     }.bind(this)).on('end', function() {
-      if (throttler) throttler.clear();
       if (done) done();
 
+      // Run any pending reads that may be queued
+      debouncedRead.flush();
+
       // Files that absent in current directory snapshot
       // but present in previous emit `remove` event
       // and are removed from @watched[directory].
@@ -401,20 +401,35 @@ function(dir, stats, initialAdd, depth, target, wh, callback) {
     }.bind(this)).on('error', this._handleError.bind(this));
   }.bind(this);
 
+  // Create a debounced version of read
+  debouncedRead = debounce(read, 1000, {
+    leading: true,
+    trailing: true,
+    maxWait: 1000
+  });
+
   var closer;
 
   if (this.options.depth == null || depth <= this.options.depth) {
     if (!target) read(dir, initialAdd, callback);
     closer = this._watchWithNodeFs(dir, function(dirPath, stats) {
       // if current directory is removed, do nothing
       if (stats && stats.mtime.getTime() === 0) return;
-
-      read(dirPath, false);
+      debouncedRead(dirPath, false);
     });
   } else {
     callback();
   }
-  return closer;
+
+  // Close function that calls fs closer and cancels any pending debounced reads
+  return function () {
+    if (closer) {
+      closer();
+    }
+
+    // Cancel any pending reads that may be queued
+    debouncedRead.cancel();
+  };
 };
 
 // Private method: Handle added file, directory, or glob pattern.

package.json

@@ -51,6 +51,7 @@
     "inherits": "^2.0.1",
     "is-binary-path": "^1.0.0",
     "is-glob": "^4.0.0",
+    "lodash.debounce": "^4.0.8",
     "normalize-path": "^2.1.1",
     "path-is-absolute": "^1.0.0",
     "readdirp": "^2.0.0",