improve backwards-compatibility

src/Type/YMap.js

@@ -34,6 +34,9 @@ export default class YMap extends Type {
     }
     return map
   }
+  keys () {
+    return this._map.keys()
+  }
   delete (key) {
     this._transact((y) => {
       let c = this._map.get(key)
@@ -58,6 +61,7 @@ export default class YMap extends Type {
       let v
       if (typeof value === 'function') {
         v = new value() // eslint-disable-line new-cap
+        value = v
       } else if (value instanceof Item) {
         v = value
       } else {

src/Type/y-xml/YXmlElement.js

@@ -11,7 +11,7 @@ export default class YXmlElement extends YXmlFragment {
     this._scrollElement = null
     if (typeof arg1 === 'string') {
       this.nodeName = arg1.toUpperCase()
-    } else if (arg1 != null && arg1.nodeType != null && arg1.nodeType === document.ELEMENT_NODE) {
+    } else if (arg1 != null && arg1.nodeType != null && arg1.nodeType === arg1.ELEMENT_NODE) {
       this.nodeName = arg1.nodeName
       this._setDom(arg1)
     } else {

src/Type/y-xml/YXmlFragment.js

@@ -17,9 +17,9 @@ function domToYXml (parent, doms) {
     }
     if (parent._domFilter(d, []) !== null) {
       let type
-      if (d.nodeType === document.TEXT_NODE) {
+      if (d.nodeType === d.TEXT_NODE) {
         type = new YXmlText(d)
-      } else if (d.nodeType === document.ELEMENT_NODE) {
+      } else if (d.nodeType === d.ELEMENT_NODE) {
         type = new YXmlFragment._YXmlElement(d, parent._domFilter)
       } else {
         throw new Error('Unsupported node!')

src/Type/y-xml/YXmlText.js

@@ -5,7 +5,7 @@ export default class YXmlText extends YText {
     let dom = null
     let initialText = null
     if (arg1 != null) {
-      if (arg1.nodeType === document.TEXT_NODE) {
+      if (arg1.nodeType != null && arg1.nodeType === arg1.TEXT_NODE) {
         dom = arg1
         initialText = dom.nodeValue
       } else if (typeof arg1 === 'string') {