diff --git a/src/types/YText.js b/src/types/YText.js
index a38dc867..93537c7b 100644
--- a/src/types/YText.js
+++ b/src/types/YText.js
@@ -502,14 +502,6 @@ const deleteText = (transaction, currPos, length) => {
   * @typedef {Object} TextAttributes
   */
 
-/**
- * @typedef {Object} DeltaItem
- * @property {number|undefined} DeltaItem.delete
- * @property {number|undefined} DeltaItem.retain
- * @property {string|undefined} DeltaItem.insert
- * @property {Object<string,any>} DeltaItem.attributes
- */
-
 /**
  * Event that describes the changes on a YText type.
  */
@@ -521,10 +513,6 @@ export class YTextEvent extends YEvent {
    */
   constructor (ytext, transaction, subs) {
     super(ytext, transaction)
-    /**
-     * @type {Array<DeltaItem>|null}
-     */
-    this._delta = null
     /**
      * Whether the children changed.
      * @type {Boolean}
@@ -545,20 +533,41 @@ export class YTextEvent extends YEvent {
     })
   }
 
+  /**
+   * @type {{added:Set<Item>,deleted:Set<Item>,keys:Map<string,{action:'add'|'update'|'delete',oldValue:any}>,delta:Array<{insert?:Array<any>|string, delete?:number, retain?:number}>}}
+   */
+  get changes () {
+    if (this._changes === null) {
+      /**
+       * @type {{added:Set<Item>,deleted:Set<Item>,keys:Map<string,{action:'add'|'update'|'delete',oldValue:any}>,delta:Array<{insert?:Array<any>|string, delete?:number, retain?:number}>}}
+       */
+      const changes = {
+        keys: this.keys,
+        delta: this.delta,
+        added: new Set(),
+        deleted: new Set()
+      }
+      this._changes = changes
+    }
+    return /** @type {any} */ (this._changes)
+  }
+
   /**
    * Compute the changes in the delta format.
    * A {@link https://quilljs.com/docs/delta/|Quill Delta}) that represents the changes on the document.
    *
-   * @type {Array<DeltaItem>}
+   * @type {Array<{insert?:string, delete?:number, retain?:number, attributes?: Object<string,any>}>}
    *
    * @public
    */
   get delta () {
     if (this._delta === null) {
       const y = /** @type {Doc} */ (this.target.doc)
-      this._delta = []
+      /**
+       * @type {Array<{insert?:string, delete?:number, retain?:number, attributes?: Object<string,any>}>}
+       */
+      const delta = []
       transact(y, transaction => {
-        const delta = /** @type {Array<DeltaItem>} */ (this._delta)
         const currentAttributes = new Map() // saves all current attributes for insert
         const oldAttributes = new Map()
         let item = this.target._start
@@ -728,8 +737,9 @@ export class YTextEvent extends YEvent {
           }
         }
       })
+      this._delta = delta
     }
-    return this._delta
+    return /** @type {any} */ (this._delta)
   }
 }
 
diff --git a/src/utils/YEvent.js b/src/utils/YEvent.js
index ff4e7339..cfbb9123 100644
--- a/src/utils/YEvent.js
+++ b/src/utils/YEvent.js
@@ -35,6 +35,14 @@ export class YEvent {
      * @type {Object|null}
      */
     this._changes = null
+    /**
+     * @type {null | Map<string, { action: 'add' | 'update' | 'delete', oldValue: any, newValue: any }>}
+     */
+    this._keys = null
+    /**
+     * @type {null | Array<{ insert?: string | Array<any>, retain?: number, delete?: number, attributes?: Object<string, any> }>}
+     */
+    this._delta = null
   }
 
   /**
@@ -67,6 +75,66 @@ export class YEvent {
     return isDeleted(this.transaction.deleteSet, struct.id)
   }
 
+  /**
+   * @type {Map<string, { action: 'add' | 'update' | 'delete', oldValue: any, newValue: any }>}
+   */
+  get keys () {
+    if (this._keys === null) {
+      const keys = new Map()
+      const target = this.target
+      const changed = /** @type Set<string|null> */ (this.transaction.changed.get(target))
+      changed.forEach(key => {
+        if (key !== null) {
+          const item = /** @type {Item} */ (target._map.get(key))
+          /**
+           * @type {'delete' | 'add' | 'update'}
+           */
+          let action
+          let oldValue
+          if (this.adds(item)) {
+            let prev = item.left
+            while (prev !== null && this.adds(prev)) {
+              prev = prev.left
+            }
+            if (this.deletes(item)) {
+              if (prev !== null && this.deletes(prev)) {
+                action = 'delete'
+                oldValue = array.last(prev.content.getContent())
+              } else {
+                return
+              }
+            } else {
+              if (prev !== null && this.deletes(prev)) {
+                action = 'update'
+                oldValue = array.last(prev.content.getContent())
+              } else {
+                action = 'add'
+                oldValue = undefined
+              }
+            }
+          } else {
+            if (this.deletes(item)) {
+              action = 'delete'
+              oldValue = array.last(/** @type {Item} */ item.content.getContent())
+            } else {
+              return // nop
+            }
+          }
+          keys.set(key, { action, oldValue })
+        }
+      })
+      this._keys = keys
+    }
+    return this._keys
+  }
+
+  /**
+   * @type {Array<{insert?: string | Array<any>, retain?: number, delete?: number, attributes?: Object<string, any>}>}
+   */
+  get delta () {
+    return this.changes.delta
+  }
+
   /**
    * Check if a struct is added by this event.
    *
@@ -80,7 +148,7 @@ export class YEvent {
   }
 
   /**
-   * @return {{added:Set<Item>,deleted:Set<Item>,keys:Map<string,{action:'add'|'update'|'delete',oldValue:any}>,delta:Array<{insert:Array<any>}|{delete:number}|{retain:number}>}}
+   * @type {{added:Set<Item>,deleted:Set<Item>,keys:Map<string,{action:'add'|'update'|'delete',oldValue:any}>,delta:Array<{insert?:Array<any>|string, delete?:number, retain?:number}>}}
    */
   get changes () {
     let changes = this._changes
@@ -92,12 +160,11 @@ export class YEvent {
        * @type {Array<{insert:Array<any>}|{delete:number}|{retain:number}>}
        */
       const delta = []
-      /**
-       * @type {Map<string,{ action: 'add' | 'update' | 'delete', oldValue: any}>}
-       */
-      const keys = new Map()
       changes = {
-        added, deleted, delta, keys
+        added,
+        deleted,
+        delta,
+        keys: this.keys
       }
       const changed = /** @type Set<string|null> */ (this.transaction.changed.get(target))
       if (changed.has(null)) {
@@ -141,46 +208,6 @@ export class YEvent {
           packOp()
         }
       }
-      changed.forEach(key => {
-        if (key !== null) {
-          const item = /** @type {Item} */ (target._map.get(key))
-          /**
-           * @type {'delete' | 'add' | 'update'}
-           */
-          let action
-          let oldValue
-          if (this.adds(item)) {
-            let prev = item.left
-            while (prev !== null && this.adds(prev)) {
-              prev = prev.left
-            }
-            if (this.deletes(item)) {
-              if (prev !== null && this.deletes(prev)) {
-                action = 'delete'
-                oldValue = array.last(prev.content.getContent())
-              } else {
-                return
-              }
-            } else {
-              if (prev !== null && this.deletes(prev)) {
-                action = 'update'
-                oldValue = array.last(prev.content.getContent())
-              } else {
-                action = 'add'
-                oldValue = undefined
-              }
-            }
-          } else {
-            if (this.deletes(item)) {
-              action = 'delete'
-              oldValue = array.last(/** @type {Item} */ item.content.getContent())
-            } else {
-              return // nop
-            }
-          }
-          keys.set(key, { action, oldValue })
-        }
-      })
       this._changes = changes
     }
     return /** @type {any} */ (changes)