implement .clone, .slice, and yxml.get

src/types/YXmlFragment.js

@@ -14,6 +14,8 @@ import {
   YXmlFragmentRefID,
   callTypeObservers,
   transact,
+  typeListGet,
+  typeListSlice,
   AbstractUpdateDecoder, AbstractUpdateEncoder, Doc, ContentType, Transaction, Item, YXmlText, YXmlHook, Snapshot // eslint-disable-line
 } from '../internals.js'
 
@@ -148,6 +150,16 @@ export class YXmlFragment extends AbstractType {
     return new YXmlFragment()
   }
 
+  /**
+   * @return {YXmlFragment}
+   */
+  clone () {
+    const el = new YXmlFragment()
+    // @ts-ignore
+    el.insert(0, el.toArray().map(item => item instanceof AbstractType ? item.clone() : item))
+    return el
+  }
+
   get length () {
     return this._prelimContent === null ? this._length : this._prelimContent.length
   }
@@ -316,6 +328,45 @@ export class YXmlFragment extends AbstractType {
     return typeListToArray(this)
   }
 
+  /**
+   * Appends content to this YArray.
+   *
+   * @param {Array<YXmlElement|YXmlText>} content Array of content to append.
+   */
+  push (content) {
+    this.insert(this.length, content)
+  }
+
+  /**
+   * Preppends content to this YArray.
+   *
+   * @param {Array<YXmlElement|YXmlText>} content Array of content to preppend.
+   */
+  unshift (content) {
+    this.insert(0, content)
+  }
+
+  /**
+   * Returns the i-th element from a YArray.
+   *
+   * @param {number} index The index of the element to return from the YArray
+   * @return {YXmlElement|YXmlText}
+   */
+  get (index) {
+    return typeListGet(this, index)
+  }
+
+  /**
+   * Transforms this YArray to a JavaScript Array.
+   *
+   * @param {number} [start]
+   * @param {number} [end]
+   * @return {Array<YXmlElement|YXmlText>}
+   */
+  slice (start = 0, end = this.length) {
+    return typeListSlice(this, start, end)
+  }
+
   /**
    * Transform the properties of this type to binary and write it to an
    * BinaryEncoder.