diff --git a/src/DocumentIndex.js b/src/DocumentIndex.js
index ae1d55d..c114d2d 100644
--- a/src/DocumentIndex.js
+++ b/src/DocumentIndex.js
@@ -12,11 +12,12 @@ class DocumentIndex {
   }
 
   updateIndex (oplog, onProgressCallback) {
-    const reducer = (handled, item, idx) => {
-      if (item.payload.op === 'PUTALL' && item.payload.docs[Symbol.iterator]) {
+    const values = oplog.values
+      for (let i  = 0; i <= values.length -1; i++) {
+      const item = values[i]
+      if (item.payload.op === 'PUTALL' && item.payload.docs && item.payload.docs[Symbol.iterator]) {
         for (const doc of item.payload.docs) {
-          if (doc && handled[doc.key] !== true) {
-            handled[doc.key] = true
+          if (doc) {
             this._index[doc.key] = {
               payload: {
                 op: 'PUT',
@@ -26,22 +27,19 @@ class DocumentIndex {
             }
           }
         }
-      } else if (handled[item.payload.key] !== true) {
-        handled[item.payload.key] = true
-        if (item.payload.op === 'PUT') {
+      } if (item.payload.op === 'PUT') {
           this._index[item.payload.key] = item
         } else if (item.payload.op === 'DEL') {
           delete this._index[item.payload.key]
+        } else if (item.payload.op === 'SET') {
+          if (this._index[item.payload.key]) {
+            Object.assign(this._index[item.payload.key].payload.value,item.payload.value)
+          }
         }
+      if (onProgressCallback) {
+        onProgressCallback(item, values.length - i)
       }
-      if (onProgressCallback) onProgressCallback(item, idx)
-      return handled
     }
-
-    oplog.values
-      .slice()
-      .reverse()
-      .reduce(reducer, {})
   }
 }
 
diff --git a/src/DocumentStore.js b/src/DocumentStore.js
index 4af323a..de6144e 100644
--- a/src/DocumentStore.js
+++ b/src/DocumentStore.js
@@ -97,6 +97,16 @@ class DocumentStore extends Store {
       value: null
     }, options)
   }
+
+  set (key, edits = {}, options = {}) {
+    if (!this._index.get(key)) { throw new Error(`No entry with key '${key}' in the database`) }
+      
+    return this._addOperation({
+      op: 'SET',
+      key: key,
+      value: edits
+    }, options)
+  }
 }
 
 module.exports = DocumentStore