diff --git a/package-lock.json b/package-lock.json
index b6697ca1..9141e6ad 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1332,9 +1332,9 @@
       "dev": true
     },
     "isomorphic.js": {
-      "version": "0.1.1",
-      "resolved": "https://registry.npmjs.org/isomorphic.js/-/isomorphic.js-0.1.1.tgz",
-      "integrity": "sha512-Q85LNm6e50saL4EPWa0mWEYNUuV51n623gzPVNC1QiLGLmjONEtfFT3pa04OoUIYB7rzGJBpzO2iNPhV1Ib4hg=="
+      "version": "0.1.3",
+      "resolved": "https://registry.npmjs.org/isomorphic.js/-/isomorphic.js-0.1.3.tgz",
+      "integrity": "sha512-pabBRLDwYefSsNS+qCazJ97o7P5xDTrNoxSYFTM09JlZTxPrOEPGKekwqUy3/Np4C4PHnVUXHYsZPOix0jELsA=="
     },
     "js-tokens": {
       "version": "4.0.0",
@@ -1439,9 +1439,9 @@
       }
     },
     "lib0": {
-      "version": "0.2.7",
-      "resolved": "https://registry.npmjs.org/lib0/-/lib0-0.2.7.tgz",
-      "integrity": "sha512-25ojhgEondpayWt2mgVTKels6R8viO27AetFgvdOk+WWGVah+q2pXouQ6dGj/gtxNwCDD2ih2B0LbDovNEtCrg==",
+      "version": "0.2.12",
+      "resolved": "https://registry.npmjs.org/lib0/-/lib0-0.2.12.tgz",
+      "integrity": "sha512-ileLyIMsWqcpyFLP6WMIgD6C7rkwrdYjH6CCFvAnqOhnGcyAl8LmLkiryVNmKW0sLRw/gLcB47LGXJDw0tDlkg==",
       "requires": {
         "isomorphic.js": "^0.1.1"
       }
@@ -2291,9 +2291,9 @@
       }
     },
     "rollup": {
-      "version": "1.29.1",
-      "resolved": "https://registry.npmjs.org/rollup/-/rollup-1.29.1.tgz",
-      "integrity": "sha512-dGQ+b9d1FOX/gluiggTAVnTvzQZUEkCi/TwZcax7ujugVRHs0nkYJlV9U4hsifGEMojnO+jvEML2CJQ6qXgbHA==",
+      "version": "1.30.0",
+      "resolved": "https://registry.npmjs.org/rollup/-/rollup-1.30.0.tgz",
+      "integrity": "sha512-ANcmfaSQwpcJtZUTA0ZMNBtFcQ1B4A5FldlNqEK0WdWm9sHSKu93ffa2KV1ux8HA/yKIV/ZARV28m7rNdXJgEw==",
       "dev": true,
       "requires": {
         "@types/estree": "*",
diff --git a/package.json b/package.json
index 7275715a..39432b7a 100644
--- a/package.json
+++ b/package.json
@@ -56,7 +56,7 @@
   },
   "homepage": "https://yjs.dev",
   "dependencies": {
-    "lib0": "^0.2.7"
+    "lib0": "^0.2.12"
   },
   "devDependencies": {
     "@rollup/plugin-commonjs": "^11.0.1",
@@ -65,7 +65,7 @@
     "http-server": "^0.12.1",
     "jsdoc": "^3.6.3",
     "markdownlint-cli": "^0.19.0",
-    "rollup": "^1.29.1",
+    "rollup": "^1.30.0",
     "rollup-cli": "^1.0.9",
     "standard": "^14.0.0",
     "tui-jsdoc-template": "^1.2.2",
diff --git a/src/types/YText.js b/src/types/YText.js
index 2f87e9ed..572bba9e 100644
--- a/src/types/YText.js
+++ b/src/types/YText.js
@@ -617,6 +617,11 @@ export class YText extends AbstractType {
     this._pending = string !== undefined ? [() => this.insert(0, string)] : []
   }
 
+  /**
+   * Number of characters of this text type.
+   *
+   * @type {number}
+   */
   get length () {
     return this._length
   }