diff --git a/examples/chat/index.js b/examples/chat/index.js
index c7717770..c2cdc8c2 100644
--- a/examples/chat/index.js
+++ b/examples/chat/index.js
@@ -10,7 +10,7 @@ var y = new Y({
 
 window.yChat = y
 
-let chatprotocol = y.get('chatprotocol', Y.Array)
+let chatprotocol = y.define('chatprotocol', Y.Array)
 
 let chatcontainer = document.querySelector('#chat')
 
diff --git a/examples/html-editor/index.js b/examples/html-editor/index.js
index 307cb34a..e91883e4 100644
--- a/examples/html-editor/index.js
+++ b/examples/html-editor/index.js
@@ -10,7 +10,7 @@ let y = new Y({
   }
 })
 window.yXml = y
-window.yXmlType = y.get('xml', Y.XmlFragment)
+window.yXmlType = y.define('xml', Y.XmlFragment)
 window.onload = function () {
   console.log('start!')
   // Bind children of XmlFragment to the document.body
diff --git a/package-lock.json b/package-lock.json
index f22e3a8d..ee979298 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1039,6 +1039,7 @@
       "requires": {
         "anymatch": "1.3.0",
         "async-each": "1.0.1",
+        "fsevents": "1.1.2",
         "glob-parent": "2.0.0",
         "inherits": "2.0.3",
         "is-binary-path": "1.0.1",
@@ -2038,6 +2039,905 @@
       "integrity": "sha1-FQStJSMVjKpA20onh8sBQRmU6k8=",
       "dev": true
     },
+    "fsevents": {
+      "version": "1.1.2",
+      "resolved": "https://registry.npmjs.org/fsevents/-/fsevents-1.1.2.tgz",
+      "integrity": "sha512-Sn44E5wQW4bTHXvQmvSHwqbuiXtduD6Rrjm2ZtUEGbyrig+nUH3t/QD4M4/ZXViY556TBpRgZkHLDx3JxPwxiw==",
+      "dev": true,
+      "optional": true,
+      "requires": {
+        "nan": "2.7.0",
+        "node-pre-gyp": "0.6.36"
+      },
+      "dependencies": {
+        "abbrev": {
+          "version": "1.1.0",
+          "bundled": true,
+          "dev": true,
+          "optional": true
+        },
+        "ajv": {
+          "version": "4.11.8",
+          "bundled": true,
+          "dev": true,
+          "optional": true,
+          "requires": {
+            "co": "4.6.0",
+            "json-stable-stringify": "1.0.1"
+          }
+        },
+        "ansi-regex": {
+          "version": "2.1.1",
+          "bundled": true,
+          "dev": true
+        },
+        "aproba": {
+          "version": "1.1.1",
+          "bundled": true,
+          "dev": true,
+          "optional": true
+        },
+        "are-we-there-yet": {
+          "version": "1.1.4",
+          "bundled": true,
+          "dev": true,
+          "optional": true,
+          "requires": {
+            "delegates": "1.0.0",
+            "readable-stream": "2.2.9"
+          }
+        },
+        "asn1": {
+          "version": "0.2.3",
+          "bundled": true,
+          "dev": true,
+          "optional": true
+        },
+        "assert-plus": {
+          "version": "0.2.0",
+          "bundled": true,
+          "dev": true,
+          "optional": true
+        },
+        "asynckit": {
+          "version": "0.4.0",
+          "bundled": true,
+          "dev": true,
+          "optional": true
+        },
+        "aws-sign2": {
+          "version": "0.6.0",
+          "bundled": true,
+          "dev": true,
+          "optional": true
+        },
+        "aws4": {
+          "version": "1.6.0",
+          "bundled": true,
+          "dev": true,
+          "optional": true
+        },
+        "balanced-match": {
+          "version": "0.4.2",
+          "bundled": true,
+          "dev": true
+        },
+        "bcrypt-pbkdf": {
+          "version": "1.0.1",
+          "bundled": true,
+          "dev": true,
+          "optional": true,
+          "requires": {
+            "tweetnacl": "0.14.5"
+          }
+        },
+        "block-stream": {
+          "version": "0.0.9",
+          "bundled": true,
+          "dev": true,
+          "requires": {
+            "inherits": "2.0.3"
+          }
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+          "version": "2.10.1",
+          "bundled": true,
+          "dev": true,
+          "requires": {
+            "hoek": "2.16.3"
+          }
+        },
+        "brace-expansion": {
+          "version": "1.1.7",
+          "bundled": true,
+          "dev": true,
+          "requires": {
+            "balanced-match": "0.4.2",
+            "concat-map": "0.0.1"
+          }
+        },
+        "buffer-shims": {
+          "version": "1.0.0",
+          "bundled": true,
+          "dev": true
+        },
+        "caseless": {
+          "version": "0.12.0",
+          "bundled": true,
+          "dev": true,
+          "optional": true
+        },
+        "co": {
+          "version": "4.6.0",
+          "bundled": true,
+          "dev": true,
+          "optional": true
+        },
+        "code-point-at": {
+          "version": "1.1.0",
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+          "dev": true
+        },
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+          "version": "1.0.5",
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+          }
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+          "bundled": true,
+          "dev": true
+        },
+        "console-control-strings": {
+          "version": "1.1.0",
+          "bundled": true,
+          "dev": true
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+        "core-util-is": {
+          "version": "1.0.2",
+          "bundled": true,
+          "dev": true
+        },
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+          "version": "2.0.5",
+          "bundled": true,
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+          "version": "2.1.4",
+          "bundled": true,
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+            "combined-stream": "1.0.5",
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+          "dev": true
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+          "version": "1.0.11",
+          "bundled": true,
+          "dev": true,
+          "requires": {
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+            "inherits": "2.0.3",
+            "mkdirp": "0.5.1",
+            "rimraf": "2.6.1"
+          }
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+            "fstream": "1.0.11",
+            "inherits": "2.0.3",
+            "minimatch": "3.0.4"
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+        "gauge": {
+          "version": "2.7.4",
+          "bundled": true,
+          "dev": true,
+          "optional": true,
+          "requires": {
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+            "console-control-strings": "1.1.0",
+            "has-unicode": "2.0.1",
+            "object-assign": "4.1.1",
+            "signal-exit": "3.0.2",
+            "string-width": "1.0.2",
+            "strip-ansi": "3.0.1",
+            "wide-align": "1.1.2"
+          }
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+          "version": "7.1.2",
+          "bundled": true,
+          "dev": true,
+          "requires": {
+            "fs.realpath": "1.0.0",
+            "inflight": "1.0.6",
+            "inherits": "2.0.3",
+            "minimatch": "3.0.4",
+            "once": "1.4.0",
+            "path-is-absolute": "1.0.1"
+          }
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+          "version": "4.1.11",
+          "bundled": true,
+          "dev": true
+        },
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+          "version": "1.0.5",
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+          "optional": true,
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+            "har-schema": "1.0.5"
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+          "version": "2.0.1",
+          "bundled": true,
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+        },
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+          "version": "3.1.3",
+          "bundled": true,
+          "dev": true,
+          "optional": true,
+          "requires": {
+            "boom": "2.10.1",
+            "cryptiles": "2.0.5",
+            "hoek": "2.16.3",
+            "sntp": "1.0.9"
+          }
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+          "version": "2.16.3",
+          "bundled": true,
+          "dev": true
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+            "jsprim": "1.4.0",
+            "sshpk": "1.13.0"
+          }
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+          "version": "1.0.6",
+          "bundled": true,
+          "dev": true,
+          "requires": {
+            "once": "1.4.0",
+            "wrappy": "1.0.2"
+          }
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+          "version": "2.0.3",
+          "bundled": true,
+          "dev": true
+        },
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+          "version": "1.3.4",
+          "bundled": true,
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+          "optional": true
+        },
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+          "version": "1.0.0",
+          "bundled": true,
+          "dev": true,
+          "requires": {
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+          }
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+          "dev": true,
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+          "requires": {
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+          "dev": true,
+          "optional": true
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+          "bundled": true,
+          "dev": true,
+          "optional": true
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+          "dev": true,
+          "optional": true,
+          "requires": {
+            "jsonify": "0.0.0"
+          }
+        },
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+          "version": "5.0.1",
+          "bundled": true,
+          "dev": true,
+          "optional": true
+        },
+        "jsonify": {
+          "version": "0.0.0",
+          "bundled": true,
+          "dev": true,
+          "optional": true
+        },
+        "jsprim": {
+          "version": "1.4.0",
+          "bundled": true,
+          "dev": true,
+          "optional": true,
+          "requires": {
+            "assert-plus": "1.0.0",
+            "extsprintf": "1.0.2",
+            "json-schema": "0.2.3",
+            "verror": "1.3.6"
+          },
+          "dependencies": {
+            "assert-plus": {
+              "version": "1.0.0",
+              "bundled": true,
+              "dev": true,
+              "optional": true
+            }
+          }
+        },
+        "mime-db": {
+          "version": "1.27.0",
+          "bundled": true,
+          "dev": true
+        },
+        "mime-types": {
+          "version": "2.1.15",
+          "bundled": true,
+          "dev": true,
+          "requires": {
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+          }
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+          "version": "3.0.4",
+          "bundled": true,
+          "dev": true,
+          "requires": {
+            "brace-expansion": "1.1.7"
+          }
+        },
+        "minimist": {
+          "version": "0.0.8",
+          "bundled": true,
+          "dev": true
+        },
+        "mkdirp": {
+          "version": "0.5.1",
+          "bundled": true,
+          "dev": true,
+          "requires": {
+            "minimist": "0.0.8"
+          }
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+        "ms": {
+          "version": "2.0.0",
+          "bundled": true,
+          "dev": true,
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+            "nopt": "4.0.1",
+            "npmlog": "4.1.0",
+            "rc": "1.2.1",
+            "request": "2.81.0",
+            "rimraf": "2.6.1",
+            "semver": "5.3.0",
+            "tar": "2.2.1",
+            "tar-pack": "3.4.0"
+          }
+        },
+        "nopt": {
+          "version": "4.0.1",
+          "bundled": true,
+          "dev": true,
+          "optional": true,
+          "requires": {
+            "abbrev": "1.1.0",
+            "osenv": "0.1.4"
+          }
+        },
+        "npmlog": {
+          "version": "4.1.0",
+          "bundled": true,
+          "dev": true,
+          "optional": true,
+          "requires": {
+            "are-we-there-yet": "1.1.4",
+            "console-control-strings": "1.1.0",
+            "gauge": "2.7.4",
+            "set-blocking": "2.0.0"
+          }
+        },
+        "number-is-nan": {
+          "version": "1.0.1",
+          "bundled": true,
+          "dev": true
+        },
+        "oauth-sign": {
+          "version": "0.8.2",
+          "bundled": true,
+          "dev": true,
+          "optional": true
+        },
+        "object-assign": {
+          "version": "4.1.1",
+          "bundled": true,
+          "dev": true,
+          "optional": true
+        },
+        "once": {
+          "version": "1.4.0",
+          "bundled": true,
+          "dev": true,
+          "requires": {
+            "wrappy": "1.0.2"
+          }
+        },
+        "os-homedir": {
+          "version": "1.0.2",
+          "bundled": true,
+          "dev": true,
+          "optional": true
+        },
+        "os-tmpdir": {
+          "version": "1.0.2",
+          "bundled": true,
+          "dev": true,
+          "optional": true
+        },
+        "osenv": {
+          "version": "0.1.4",
+          "bundled": true,
+          "dev": true,
+          "optional": true,
+          "requires": {
+            "os-homedir": "1.0.2",
+            "os-tmpdir": "1.0.2"
+          }
+        },
+        "path-is-absolute": {
+          "version": "1.0.1",
+          "bundled": true,
+          "dev": true
+        },
+        "performance-now": {
+          "version": "0.2.0",
+          "bundled": true,
+          "dev": true,
+          "optional": true
+        },
+        "process-nextick-args": {
+          "version": "1.0.7",
+          "bundled": true,
+          "dev": true
+        },
+        "punycode": {
+          "version": "1.4.1",
+          "bundled": true,
+          "dev": true,
+          "optional": true
+        },
+        "qs": {
+          "version": "6.4.0",
+          "bundled": true,
+          "dev": true,
+          "optional": true
+        },
+        "rc": {
+          "version": "1.2.1",
+          "bundled": true,
+          "dev": true,
+          "optional": true,
+          "requires": {
+            "deep-extend": "0.4.2",
+            "ini": "1.3.4",
+            "minimist": "1.2.0",
+            "strip-json-comments": "2.0.1"
+          },
+          "dependencies": {
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+              "version": "1.2.0",
+              "bundled": true,
+              "dev": true,
+              "optional": true
+            }
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+        },
+        "readable-stream": {
+          "version": "2.2.9",
+          "bundled": true,
+          "dev": true,
+          "requires": {
+            "buffer-shims": "1.0.0",
+            "core-util-is": "1.0.2",
+            "inherits": "2.0.3",
+            "isarray": "1.0.0",
+            "process-nextick-args": "1.0.7",
+            "string_decoder": "1.0.1",
+            "util-deprecate": "1.0.2"
+          }
+        },
+        "request": {
+          "version": "2.81.0",
+          "bundled": true,
+          "dev": true,
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+            "extend": "3.0.1",
+            "forever-agent": "0.6.1",
+            "form-data": "2.1.4",
+            "har-validator": "4.2.1",
+            "hawk": "3.1.3",
+            "http-signature": "1.1.1",
+            "is-typedarray": "1.0.0",
+            "isstream": "0.1.2",
+            "json-stringify-safe": "5.0.1",
+            "mime-types": "2.1.15",
+            "oauth-sign": "0.8.2",
+            "performance-now": "0.2.0",
+            "qs": "6.4.0",
+            "safe-buffer": "5.0.1",
+            "stringstream": "0.0.5",
+            "tough-cookie": "2.3.2",
+            "tunnel-agent": "0.6.0",
+            "uuid": "3.0.1"
+          }
+        },
+        "rimraf": {
+          "version": "2.6.1",
+          "bundled": true,
+          "dev": true,
+          "requires": {
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+          }
+        },
+        "safe-buffer": {
+          "version": "5.0.1",
+          "bundled": true,
+          "dev": true
+        },
+        "semver": {
+          "version": "5.3.0",
+          "bundled": true,
+          "dev": true,
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+        },
+        "set-blocking": {
+          "version": "2.0.0",
+          "bundled": true,
+          "dev": true,
+          "optional": true
+        },
+        "signal-exit": {
+          "version": "3.0.2",
+          "bundled": true,
+          "dev": true,
+          "optional": true
+        },
+        "sntp": {
+          "version": "1.0.9",
+          "bundled": true,
+          "dev": true,
+          "optional": true,
+          "requires": {
+            "hoek": "2.16.3"
+          }
+        },
+        "sshpk": {
+          "version": "1.13.0",
+          "bundled": true,
+          "dev": true,
+          "optional": true,
+          "requires": {
+            "asn1": "0.2.3",
+            "assert-plus": "1.0.0",
+            "bcrypt-pbkdf": "1.0.1",
+            "dashdash": "1.14.1",
+            "ecc-jsbn": "0.1.1",
+            "getpass": "0.1.7",
+            "jodid25519": "1.0.2",
+            "jsbn": "0.1.1",
+            "tweetnacl": "0.14.5"
+          },
+          "dependencies": {
+            "assert-plus": {
+              "version": "1.0.0",
+              "bundled": true,
+              "dev": true,
+              "optional": true
+            }
+          }
+        },
+        "string_decoder": {
+          "version": "1.0.1",
+          "bundled": true,
+          "dev": true,
+          "requires": {
+            "safe-buffer": "5.0.1"
+          }
+        },
+        "string-width": {
+          "version": "1.0.2",
+          "bundled": true,
+          "dev": true,
+          "requires": {
+            "code-point-at": "1.1.0",
+            "is-fullwidth-code-point": "1.0.0",
+            "strip-ansi": "3.0.1"
+          }
+        },
+        "stringstream": {
+          "version": "0.0.5",
+          "bundled": true,
+          "dev": true,
+          "optional": true
+        },
+        "strip-ansi": {
+          "version": "3.0.1",
+          "bundled": true,
+          "dev": true,
+          "requires": {
+            "ansi-regex": "2.1.1"
+          }
+        },
+        "strip-json-comments": {
+          "version": "2.0.1",
+          "bundled": true,
+          "dev": true,
+          "optional": true
+        },
+        "tar": {
+          "version": "2.2.1",
+          "bundled": true,
+          "dev": true,
+          "requires": {
+            "block-stream": "0.0.9",
+            "fstream": "1.0.11",
+            "inherits": "2.0.3"
+          }
+        },
+        "tar-pack": {
+          "version": "3.4.0",
+          "bundled": true,
+          "dev": true,
+          "optional": true,
+          "requires": {
+            "debug": "2.6.8",
+            "fstream": "1.0.11",
+            "fstream-ignore": "1.0.5",
+            "once": "1.4.0",
+            "readable-stream": "2.2.9",
+            "rimraf": "2.6.1",
+            "tar": "2.2.1",
+            "uid-number": "0.0.6"
+          }
+        },
+        "tough-cookie": {
+          "version": "2.3.2",
+          "bundled": true,
+          "dev": true,
+          "optional": true,
+          "requires": {
+            "punycode": "1.4.1"
+          }
+        },
+        "tunnel-agent": {
+          "version": "0.6.0",
+          "bundled": true,
+          "dev": true,
+          "optional": true,
+          "requires": {
+            "safe-buffer": "5.0.1"
+          }
+        },
+        "tweetnacl": {
+          "version": "0.14.5",
+          "bundled": true,
+          "dev": true,
+          "optional": true
+        },
+        "uid-number": {
+          "version": "0.0.6",
+          "bundled": true,
+          "dev": true,
+          "optional": true
+        },
+        "util-deprecate": {
+          "version": "1.0.2",
+          "bundled": true,
+          "dev": true
+        },
+        "uuid": {
+          "version": "3.0.1",
+          "bundled": true,
+          "dev": true,
+          "optional": true
+        },
+        "verror": {
+          "version": "1.3.6",
+          "bundled": true,
+          "dev": true,
+          "optional": true,
+          "requires": {
+            "extsprintf": "1.0.2"
+          }
+        },
+        "wide-align": {
+          "version": "1.1.2",
+          "bundled": true,
+          "dev": true,
+          "optional": true,
+          "requires": {
+            "string-width": "1.0.2"
+          }
+        },
+        "wrappy": {
+          "version": "1.0.2",
+          "bundled": true,
+          "dev": true
+        }
+      }
+    },
     "function-bind": {
       "version": "1.1.0",
       "resolved": "https://registry.npmjs.org/function-bind/-/function-bind-1.1.0.tgz",
@@ -2880,6 +3780,13 @@
       "integrity": "sha1-j7+rsKmKJT0xhDMfno3rc3L6xsA=",
       "dev": true
     },
+    "nan": {
+      "version": "2.7.0",
+      "resolved": "https://registry.npmjs.org/nan/-/nan-2.7.0.tgz",
+      "integrity": "sha1-2Vv3IeyHfgjbJ27T/G63j5CDrUY=",
+      "dev": true,
+      "optional": true
+    },
     "natural-compare": {
       "version": "1.4.0",
       "resolved": "https://registry.npmjs.org/natural-compare/-/natural-compare-1.4.0.tgz",
diff --git a/src/Struct/ItemJSON.js b/src/Struct/ItemJSON.js
index 8c6610bc..0cc6c835 100644
--- a/src/Struct/ItemJSON.js
+++ b/src/Struct/ItemJSON.js
@@ -35,7 +35,7 @@ export default class ItemJSON extends Item {
   _logString () {
     const left = this._left !== null ? this._left._lastId : null
     const origin = this._origin !== null ? this._origin._lastId : null
-    return `ItemJSON(id:${logID(this._id)},content:${JSON.stringify(this._content)},left:${logID(left)},origin:${logID(origin)},right:${logID(this._right)},parent:${logID(this._parent)},parentSub:${logID(this._parentSub)})`
+    return `ItemJSON(id:${logID(this._id)},content:${JSON.stringify(this._content)},left:${logID(left)},origin:${logID(origin)},right:${logID(this._right)},parent:${logID(this._parent)},parentSub:${this._parentSub})`
   }
   _splitAt (y, diff) {
     if (diff === 0) {
diff --git a/src/Struct/ItemString.js b/src/Struct/ItemString.js
index 50ea4839..a5a0b90c 100644
--- a/src/Struct/ItemString.js
+++ b/src/Struct/ItemString.js
@@ -26,7 +26,7 @@ export default class ItemString extends Item {
   _logString () {
     const left = this._left !== null ? this._left._lastId : null
     const origin = this._origin !== null ? this._origin._lastId : null
-    return `ItemJSON(id:${logID(this._id)},content:${JSON.stringify(this._content)},left:${logID(left)},origin:${logID(origin)},right:${logID(this._right)},parent:${logID(this._parent)},parentSub:${logID(this._parentSub)})`
+    return `ItemJSON(id:${logID(this._id)},content:${JSON.stringify(this._content)},left:${logID(left)},origin:${logID(origin)},right:${logID(this._right)},parent:${logID(this._parent)},parentSub:${this._parentSub})`
   }
   _splitAt (y, diff) {
     if (diff === 0) {
diff --git a/src/Type/YArray.js b/src/Type/YArray.js
index 845b758e..543969ba 100644
--- a/src/Type/YArray.js
+++ b/src/Type/YArray.js
@@ -212,6 +212,6 @@ export default class YArray extends Type {
   _logString () {
     const left = this._left !== null ? this._left._lastId : null
     const origin = this._origin !== null ? this._origin._lastId : null
-    return `YArray(id:${logID(this._id)},start:${logID(this._start)},left:${logID(left)},origin:${logID(origin)},right:${logID(this._right)},parent:${logID(this._parent)},parentSub:${logID(this._parentSub)})`
+    return `YArray(id:${logID(this._id)},start:${logID(this._start)},left:${logID(left)},origin:${logID(origin)},right:${logID(this._right)},parent:${logID(this._parent)},parentSub:${this._parentSub})`
   }
 }
diff --git a/src/Type/YMap.js b/src/Type/YMap.js
index 5a00e30a..f1403340 100644
--- a/src/Type/YMap.js
+++ b/src/Type/YMap.js
@@ -109,6 +109,6 @@ export default class YMap extends Type {
   _logString () {
     const left = this._left !== null ? this._left._lastId : null
     const origin = this._origin !== null ? this._origin._lastId : null
-    return `YMap(id:${logID(this._id)},mapSize:${this._map.size},left:${logID(left)},origin:${logID(origin)},right:${logID(this._right)},parent:${logID(this._parent)},parentSub:${logID(this._parentSub)})`
+    return `YMap(id:${logID(this._id)},mapSize:${this._map.size},left:${logID(left)},origin:${logID(origin)},right:${logID(this._right)},parent:${logID(this._parent)},parentSub:${this._parentSub})`
   }
 }
diff --git a/src/Type/YText.js b/src/Type/YText.js
index e5181571..22a1afbe 100644
--- a/src/Type/YText.js
+++ b/src/Type/YText.js
@@ -62,6 +62,6 @@ export default class YText extends YArray {
   _logString () {
     const left = this._left !== null ? this._left._lastId : null
     const origin = this._origin !== null ? this._origin._lastId : null
-    return `YText(id:${logID(this._id)},start:${logID(this._start)},left:${logID(left)},origin:${logID(origin)},right:${logID(this._right)},parent:${logID(this._parent)},parentSub:${logID(this._parentSub)})`
+    return `YText(id:${logID(this._id)},start:${logID(this._start)},left:${logID(left)},origin:${logID(origin)},right:${logID(this._right)},parent:${logID(this._parent)},parentSub:${this._parentSub})`
   }
 }
diff --git a/src/Type/y-xml/YXmlFragment.js b/src/Type/y-xml/YXmlFragment.js
index f8dd5908..96dbaf79 100644
--- a/src/Type/y-xml/YXmlFragment.js
+++ b/src/Type/y-xml/YXmlFragment.js
@@ -33,6 +33,54 @@ function domToYXml (parent, doms) {
   return types
 }
 
+class YXmlTreeWalker {
+  constructor (root, f) {
+    this._filter = f || (() => true)
+    this._root = root
+    this._currentNode = root
+    this._firstCall = true
+  }
+  [Symbol.iterator] () {
+    return this
+  }
+  next () {
+    let n = this._currentNode
+    if (this._firstCall) {
+      this._firstCall = false
+      if (!n._deleted && this._filter(n)) {
+        return { value: n, done: false }
+      }
+    }
+    do {
+      if (!n._deleted && n.constructor === YXmlFragment._YXmlElement && n._start !== null) {
+        // walk down in the tree
+        n = n._start
+      } else {
+        // walk right or up in the tree
+        while (n !== this._root) {
+          if (n._right !== null) {
+            n = n._right
+            break
+          }
+          n = n._parent
+        }
+        if (n === this._root) {
+          n = null
+        }
+      }
+      if (n === this._root) {
+        break
+      }
+    } while (n !== null && (n._deleted || !this._filter(n)))
+    this._currentNode = n
+    if (n === null) {
+      return { done: true }
+    } else {
+      return { value: n, done: false }
+    }
+  }
+}
+
 export default class YXmlFragment extends YArray {
   constructor () {
     super()
@@ -55,6 +103,33 @@ export default class YXmlFragment extends YArray {
       }
     }
   }
+  createTreeWalker (filter) {
+    return new YXmlTreeWalker(this, filter)
+  }
+  /**
+   * Retrieve first element that matches *query*
+   * Similar to DOM's querySelector, but only accepts a subset of its queries
+   *
+   * Query support:
+   *   - tagname
+   * TODO:
+   *   - id
+   *   - attribute
+   */
+  querySelector (query) {
+    query = query.toUpperCase()
+    const iterator = new YXmlTreeWalker(this, element => element.nodeName === query)
+    const next = iterator.next()
+    if (next.done) {
+      return null
+    } else {
+      return next.value
+    }
+  }
+  querySelectorAll (query) {
+    query = query.toUpperCase()
+    return Array.from(new YXmlTreeWalker(this, element => element.nodeName === query))
+  }
   enableSmartScrolling (scrollElement) {
     this._scrollElement = scrollElement
     this.forEach(xml => {
diff --git a/test/y-xml.tests.js b/test/y-xml.tests.js
index 8fd6cc6d..ccf2ba56 100644
--- a/test/y-xml.tests.js
+++ b/test/y-xml.tests.js
@@ -287,6 +287,22 @@ test('deep element insert', async function xml16 (t) {
   await compareUsers(t, users)
 })
 
+test('treeWalker', async function xml17 (t) {
+  var { users, xml0 } = await initArrays(t, { users: 3 })
+  let paragraph1 = new Y.XmlElement('p')
+  let paragraph2 = new Y.XmlElement('p')
+  let text1 = new Y.Text('init')
+  let text2 = new Y.Text('text')
+  paragraph1.insert(0, [text1, text2])
+  xml0.insert(0, [paragraph1, paragraph2, new Y.XmlElement('img')])
+  let allParagraphs = xml0.querySelectorAll('p')
+  t.assert(allParagraphs.length === 2, 'found exactly two paragraphs')
+  t.assert(allParagraphs[0] === paragraph1, 'querySelectorAll found paragraph1')
+  t.assert(allParagraphs[1] === paragraph2, 'querySelectorAll found paragraph2')
+  t.assert(xml0.querySelector('p') === paragraph1, 'querySelector found paragraph1')
+  await compareUsers(t, users)
+})
+
 // TODO: move elements
 var xmlTransactions = [
   function attributeChange (t, user, chance) {
diff --git a/tests-lib/helper.js b/tests-lib/helper.js
index bee1111e..de6dc92a 100644
--- a/tests-lib/helper.js
+++ b/tests-lib/helper.js
@@ -150,9 +150,9 @@ export async function initArrays (t, opts) {
       connector: connOpts
     })
     result.users.push(y)
-    result['array' + i] = y.get('array', Y.Array)
-    result['map' + i] = y.get('map', Y.Map)
-    result['xml' + i] = y.get('xml', Y.XmlElement)
+    result['array' + i] = y.define('array', Y.Array)
+    result['map' + i] = y.define('map', Y.Map)
+    result['xml' + i] = y.define('xml', Y.XmlElement)
     y.get('xml', Y.Xml).setDomFilter(function (d, attrs) {
       if (d.nodeName === 'HIDDEN') {
         return null