perf(diff): add fail fasts

thi-ng · Feb 2, 2018 · 448e839 · 448e839
1 parent 9848576
commit 448e839
Show file tree

Hide file tree

Showing 2 changed files with 11 additions and 5 deletions.
diff --git a/packages/diff/src/array.ts b/packages/diff/src/array.ts
@@ -20,6 +20,9 @@ export function diffArray(_a, _b) {
         const: {},
         linear: []
     };
+    if (_a === _b) {
+        return state;
+    }
     const reverse = _a.length >= _b.length,
         adds = state[reverse ? "dels" : "adds"],
         dels = state[reverse ? "adds" : "dels"],

diff --git a/packages/diff/src/object.ts b/packages/diff/src/object.ts
@@ -6,21 +6,24 @@ export function diffObject(a: any, b: any) {
     const adds = [],
         dels = [],
         edits = [],
-        keys = new Set(Object.keys(a).concat(Object.keys(b)));
-    let distance = 0;
+        keys = new Set(Object.keys(a).concat(Object.keys(b))),
+        state = <ObjectDiff>{ distance: 0, adds, dels, edits };
+    if (a === b) {
+        return state;
+    }
     for (let k of keys) {
         const va = a[k],
             vb = b[k],
             hasA = va !== undefined;
         if (hasA && vb !== undefined) {
             if (!equiv(va, vb)) {
                 edits.push([k, vb]);
-                distance++;
+                state.distance++;
             }
         } else {
             (hasA ? dels : adds).push(k);
-            distance++;
+            state.distance++;
         }
     }
-    return <ObjectDiff>{ distance, adds, dels, edits };
+    return state;
 }