From ac884e7507cdc55cf56957055d5f9c0927553c8c Mon Sep 17 00:00:00 2001
From: Anton Shchekota <anton.redfox@gmail.com>
Date: Fri, 29 Dec 2017 22:40:28 +0300
Subject: [PATCH 1/2] Optimization error in update operation

---
 src/update.js | 79 +++++++++++++--------------------------------------
 1 file changed, 20 insertions(+), 59 deletions(-)

diff --git a/src/update.js b/src/update.js
index 68e73fa..2709c32 100644
--- a/src/update.js
+++ b/src/update.js
@@ -23,6 +23,10 @@ function err(operation, expectedTarget, path) {
   );
 }
 
+const tr = true;
+const arrayMethods = {push: tr, unshift: tr, concat: tr, splice: tr, pop: tr, shift: tr};
+const objectMethods = {merge: tr, deepMerge: tr};
+
 /**
  * Function aiming at applying a single update operation on the given tree's
  * data.
@@ -43,11 +47,10 @@ export default function update(data, path, operation, opts = {}) {
 
   // Walking the path
   let p = dummy,
-      i,
-      l,
       s;
 
-  for (i = 0, l = dummyPath.length; i < l; i++) {
+  const l = dummyPath.length;
+  for (let i = 0; i < l; i++) {
 
     // Current item's reference is therefore p[s]
     // The reason why we don't create a variable here for convenience
@@ -61,6 +64,20 @@ export default function update(data, path, operation, opts = {}) {
     // If we reached the end of the path, we apply the operation
     if (i === l - 1) {
 
+      if (operationType in arrayMethods && !type.array(p[s])) {
+        throw err(
+          operationType,
+          'array',
+          currentPath
+        );
+      }
+      if (operationType in objectMethods && !type.object(p[s])) {
+        throw err(
+          operationType,
+          'object',
+          currentPath
+        );
+      }
       /**
        * Set
        */
@@ -125,13 +142,6 @@ export default function update(data, path, operation, opts = {}) {
        * Push
        */
       else if (operationType === 'push') {
-        if (!type.array(p[s]))
-          throw err(
-            'push',
-            'array',
-            currentPath
-          );
-
         if (opts.persistent)
           p[s] = p[s].concat([value]);
         else
@@ -142,13 +152,6 @@ export default function update(data, path, operation, opts = {}) {
        * Unshift
        */
       else if (operationType === 'unshift') {
-        if (!type.array(p[s]))
-          throw err(
-            'unshift',
-            'array',
-            currentPath
-          );
-
         if (opts.persistent)
           p[s] = [value].concat(p[s]);
         else
@@ -159,13 +162,6 @@ export default function update(data, path, operation, opts = {}) {
        * Concat
        */
       else if (operationType === 'concat') {
-        if (!type.array(p[s]))
-          throw err(
-            'concat',
-            'array',
-            currentPath
-          );
-
         if (opts.persistent)
           p[s] = p[s].concat(value);
         else
@@ -176,13 +172,6 @@ export default function update(data, path, operation, opts = {}) {
        * Splice
        */
       else if (operationType === 'splice') {
-        if (!type.array(p[s]))
-          throw err(
-            'splice',
-            'array',
-            currentPath
-          );
-
         if (opts.persistent)
           p[s] = splice.apply(null, [p[s]].concat(value));
         else
@@ -193,13 +182,6 @@ export default function update(data, path, operation, opts = {}) {
        * Pop
        */
       else if (operationType === 'pop') {
-        if (!type.array(p[s]))
-          throw err(
-            'pop',
-            'array',
-            currentPath
-          );
-
         if (opts.persistent)
           p[s] = splice(p[s], -1, 1);
         else
@@ -210,13 +192,6 @@ export default function update(data, path, operation, opts = {}) {
        * Shift
        */
       else if (operationType === 'shift') {
-        if (!type.array(p[s]))
-          throw err(
-            'shift',
-            'array',
-            currentPath
-          );
-
         if (opts.persistent)
           p[s] = splice(p[s], 0, 1);
         else
@@ -238,13 +213,6 @@ export default function update(data, path, operation, opts = {}) {
        * Merge
        */
       else if (operationType === 'merge') {
-        if (!type.object(p[s]))
-          throw err(
-            'merge',
-            'object',
-            currentPath
-          );
-
         if (opts.persistent)
           p[s] = shallowMerge({}, p[s], value);
         else
@@ -255,13 +223,6 @@ export default function update(data, path, operation, opts = {}) {
        * Deep merge
        */
       else if (operationType === 'deepMerge') {
-        if (!type.object(p[s]))
-          throw err(
-            'deepMerge',
-            'object',
-            currentPath
-          );
-
         if (opts.persistent)
           p[s] = deepMerge({}, p[s], value);
         else

From 987448c3c6837f53b6596a1ed116f4f734572acb Mon Sep 17 00:00:00 2001
From: Anton Shchekota <anton.redfox@gmail.com>
Date: Fri, 29 Dec 2017 22:50:09 +0300
Subject: [PATCH 2/2] Remove currentPath and use path for throw error

---
 src/update.js | 11 +++--------
 1 file changed, 3 insertions(+), 8 deletions(-)

diff --git a/src/update.js b/src/update.js
index 2709c32..dfaffaf 100644
--- a/src/update.js
+++ b/src/update.js
@@ -42,8 +42,7 @@ export default function update(data, path, operation, opts = {}) {
 
   // Dummy root, so we can shift and alter the root
   const dummy = {root: data},
-        dummyPath = ['root', ...path],
-        currentPath = [];
+        dummyPath = ['root', ...path];
 
   // Walking the path
   let p = dummy,
@@ -57,10 +56,6 @@ export default function update(data, path, operation, opts = {}) {
     // is because we actually need to mutate the reference.
     s = dummyPath[i];
 
-    // Updating the path
-    if (i > 0)
-      currentPath.push(s);
-
     // If we reached the end of the path, we apply the operation
     if (i === l - 1) {
 
@@ -68,14 +63,14 @@ export default function update(data, path, operation, opts = {}) {
         throw err(
           operationType,
           'array',
-          currentPath
+          path
         );
       }
       if (operationType in objectMethods && !type.object(p[s])) {
         throw err(
           operationType,
           'object',
-          currentPath
+          path
         );
       }
       /**