DevTools: Simplify mergeOrIntersect

Source/devtools/front_end/utilities.js

 /*
  * Copyright (C) 2007 Apple Inc.  All rights reserved.
  * Copyright (C) 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
@@ skipping 699 matching lines @@
  * @param {!Array.<T>} array2
  * @param {function(T,T):number} comparator
  * @return {!Array.<T>}
  * @template T
  */
 function mergeOrIntersect(array1, array2, comparator, mergeNotIntersect)
 {
     var result = [];
     var i = 0;
     var j = 0;
-    while (i < array1.length || j < array2.length) {
-        if (i === array1.length) {
-            result = result.concat(array2.slice(j));
-            j = array2.length;
-        } else if (j === array2.length) {
-            result = result.concat(array1.slice(i));
-            i = array1.length;
-        } else {
-            var compareValue = comparator(array1[i], array2[j])
-             if (compareValue < 0) {
-                 if (mergeNotIntersect)
-                    result.push(array1[i]);
-                 ++i;
-             } else if (compareValue > 0) {
-                 if (mergeNotIntersect)
-                     result.push(array2[j]);
-                 ++j;
-             } else {
-                 result.push(array1[i]);
-                 ++i;
-                 ++j;
-             }
-        }
+    while (i < array1.length && j < array2.length) {
+        var compareValue = comparator(array1[i], array2[j]);
+        if (mergeNotIntersect || !compareValue)
+            result.push(compareValue <= 0 ? array1[i] : array2[j]);
+        if (compareValue <= 0)
+            i++;
+        if (compareValue >= 0)
+            j++;
+    }
+    if (mergeNotIntersect) {
+        result = result.concat(array1.slice(i));

[pfeldman, 2014/02/14 16:02:17]

Isn't this expensive? Both concat and slice are creating copies.

[alph, 2014/02/14 16:31:37]

Indeed. Fixed.

+        result = result.concat(array2.slice(j));
     }
     return result;
 }
 
 Object.defineProperty(Array.prototype, "intersectOrdered",
 {
     /**
      * @param {!Array.<T>} array
      * @param {function(T,T):number} comparator
      * @return {!Array.<T>}
@@ skipping 781 matching lines @@
             this._outgoingCallback();
     }
 }
 
 /**
  * @param {*} value
  */
 function suppressUnused(value)
 {
 }