Reimplement plugin cache

Author: shockey

src/specmap/index.js

@@ -83,7 +83,7 @@ class SpecMap {
     // We might consider making this (traversing & application) configurable later.
     function createKeyBasedPlugin(pluginObj) {
       return function* (patches, specmap) {
-        const traversedRefs = {}
+        const resultCache = {}
 
         for (const patch of patches.filter(lib.isAdditiveMutation)) {
           yield* traverse(patch.value, patch.path, patch)
@@ -109,20 +109,24 @@ class SpecMap {
               // If the object has a meta '$$ref' - and store this $$ref
               // in a lookaside to prevent future traversals of this $ref's tree.
               const objRef = obj.$$ref
-              const traversed = specmap.allowMetaPatches && traversedRefs[obj.$$ref]
-
-              if (!traversed) {
-                if (isObj) {
-                  // Only store the ref if it exists
-                  if (specmap.allowMetaPatches && objRef) {
-                    traversedRefs[objRef] = true
-                  }
-                  yield* traverse(val, updatedPath, patch)
-                }
+
+              if (isObj) {
+                // console.log('recursive case', {obj, path, patch})
+                yield* traverse(val, updatedPath, patch)
               }
 
               if (!isRootProperties && key === pluginObj.key) {
-                yield pluginObj.plugin(val, key, updatedPath, specmap, patch)
+                // console.log('base case', {obj, path, patch})
+                const stringifiedPath = path.join('/')
+
+                if (resultCache[stringifiedPath]) {
+                  yield resultCache[stringifiedPath]
+                }
+                else {
+                  const res = pluginObj.plugin(val, key, updatedPath, specmap, patch)
+                  resultCache[stringifiedPath] = res
+                  yield res
+                }
               }
             }
           }