perf: support flexible buffers for file-watchers

Author: shakyShane

lib/default-config.js

@@ -367,7 +367,7 @@ module.exports = {
      * @default 0
      * @since 2.6.0
      */
-    reloadDebounce: 0,
+    reloadDebounce: 500,
 
     /**
      * Emit only the first event during sequential time windows

lib/file-event-handler.js

@@ -7,7 +7,7 @@ var utils = require("./utils");
  * @return {Rx.Observable<{type: string, files: Array<any>}>}
  */
 function fileChanges(subject, options) {
-    var operators = [
+    const operators = [
         {
             option: "reloadThrottle",
             fnName: "throttle"
@@ -18,40 +18,30 @@ function fileChanges(subject, options) {
         }
     ];
 
-    var scheduler = options.getIn(["debug", "scheduler"]);
+    const scheduler = options.getIn(["debug", "scheduler"]);
 
     /**
-     * if the 'reloadDebounce' option was provided, create
-     * a stream buffered/debounced stream of events
+     * Create a stream buffered/debounced stream of events
      */
-    var initial = (function() {
-        if (options.get("reloadDebounce") > 0) {
-            return getAggregatedDebouncedStream(subject, options, scheduler);
-        }
-        return subject;
-    })();
+    const initial = getAggregatedDebouncedStream(subject, options, scheduler);
 
-    return applyOperators(operators, initial, options, scheduler).map(function(
-        xs
-    ) {
-        var items = [].concat(xs);
-        var paths = items.map(function(x) {
-            return x.path;
-        });
+    return applyOperators(operators, initial, options, scheduler)
+        .map(function(items) {
+            const paths = items.map(x => x.path);
 
-        if (
-            utils.willCauseReload(paths, options.get("injectFileTypes").toJS())
-        ) {
+            if (
+                utils.willCauseReload(paths, options.get("injectFileTypes").toJS())
+            ) {
+                return {
+                    type: "reload",
+                    files: items
+                };
+            }
             return {
-                type: "reload",
+                type: "inject",
                 files: items
             };
-        }
-        return {
-            type: "inject",
-            files: items
-        };
-    });
+        })
 }
 module.exports.fileChanges = fileChanges;
 
@@ -113,19 +103,4 @@ function getAggregatedDebouncedStream(subject, options, scheduler) {
             return options.get("watchEvents").indexOf(x.event) > -1;
         })
         .buffer(subject.debounce(options.get("reloadDebounce"), scheduler))
-        .map(function(buffered) {
-            return buffered.reduce(function(acc, item) {
-                if (!acc[item.path]) acc[item.path] = item;
-                if (acc[item.path]) acc[item.path] = item;
-                return acc;
-            }, {});
-        })
-        .map(function(group) {
-            return Object.keys(group).map(function(key) {
-                return group[key];
-            });
-        })
-        .filter(function(x) {
-            return x.length;
-        });
 }