perf(index): Create a copy only for specified keys

Author: mrmlnc

lib/index.js

@@ -181,7 +181,7 @@ function walk (opts, nodes) {
       const keys = loopParams.keys
 
       // creates a copy of the keys that will be changed within the loop
-      const localsBackup = makeBackupLoopKeys(keys[0], keys[1], opts.locals)
+      const localsBackup = makeLocalsBackup(keys, opts.locals)
 
       // run the loop, different types of loops for arrays and objects
       if (Array.isArray(target)) {
@@ -195,7 +195,7 @@ function walk (opts, nodes) {
       }
 
       // returns the original keys values that was changed within the loop
-      opts.locals = revertBackupedLocals(keys[0], keys[1], opts.locals, localsBackup)
+      opts.locals = revertBackupedLocals(keys, opts.locals, localsBackup)
 
       // return directly out of the loop, which will skip the "each" tag
       return m
@@ -269,27 +269,31 @@ function parseLoopStatement (input) {
 }
 
 /**
- * Creates a backup of keys within the loop
+ * Creates a backup of keys values
  */
-function makeBackupLoopKeys (p1, p2, locals) {
+function makeLocalsBackup (keys, locals) {
   let backup = {}
-  if (p1 && data.locals.hasOwnProperty(p1)) backup[p1] = data.locals[p1]
-  if (p2 && data.locals.hasOwnProperty(p2)) backup[p2] = data.locals[p2]
+
+  for (let i = 0; i < keys.length; i++) {
+    const key = keys[i]
+    if (data.locals.hasOwnProperty(key)) backup[key] = cloneDeep(data.locals[key])
+  }
 
   return backup
 }
 
 /**
  * Returns the original keys values
  */
-function revertBackupedLocals (p1, p2, locals, backup) {
-  // Remove loop keys from locals
-  delete locals[p1]
-  delete locals[p2]
-
-  // Revert copied keys
-  if (p1 && backup.hasOwnProperty(p1)) locals[p1] = backup[p1]
-  if (p2 && backup.hasOwnProperty(p2)) locals[p2] = backup[p2]
+function revertBackupedLocals (keys, locals, backup) {
+  for (let i = 0; i < keys.length; i++) {
+    const key = keys[i]
+    // remove key from locals
+    delete locals[key]
+
+    // revert copied key value
+    if (backup.hasOwnProperty(key)) locals[key] = backup[key]
+  }
 
   return locals
 }