fix compiling issues

src/Util/ID.js

@@ -1,7 +1,7 @@
 
-import StructManager from './StructManager'
+import { getReference } from './structReferences.js'
 
-export class ID {
+export default class ID {
   constructor (user, clock) {
     this.user = user
     this.clock = clock
@@ -16,17 +16,3 @@ export class ID {
     return this.user < id.user || (this.user === id.user && this.clock < id.clock)
   }
 }
-
-export class RootID {
-  constructor (name, typeConstructor) {
-    this.user = -1
-    this.name = name
-    this.type = StructManager.getReference(typeConstructor)
-  }
-  equals (id) {
-    return id !== null && id.user === this.user && id.name === this.name && id.type === this.type
-  }
-  lessThan (id) {
-    return this.user < id.user || (this.user === id.user && (this.name < id.name || (this.name === id.name && this.type < id.type)))
-  }
-}

src/Util/RootID.js

@@ -0,0 +1,14 @@
+
+export default class RootID {
+  constructor (name, typeConstructor) {
+    this.user = -1
+    this.name = name
+    this.type = StructManager.getReference(typeConstructor)
+  }
+  equals (id) {
+    return id !== null && id.user === this.user && id.name === this.name && id.type === this.type
+  }
+  lessThan (id) {
+    return this.user < id.user || (this.user === id.user && (this.name < id.name || (this.name === id.name && this.type < id.type)))
+  }
+}

src/Util/deleteItemRange.js

@@ -1,7 +1,7 @@
 import Delete from '../Struct/Delete'
 import ID from './ID'
 
-export default function deleteItemRange (y, user, clock, length) {
+export function deleteItemRange (y, user, clock, length) {
   let del = new Delete()
   del._target = new ID(user, clock)
   del._length = length

src/Util/generateUserID.js

@@ -1,6 +1,6 @@
 /* global crypto */
 
-export default function generateUserID () {
+export function generateUserID () {
   if (typeof crypto !== 'undefined' && crypto.getRandomValue != null) {
     // browser
     let arr = new Uint32Array(1)

src/Util/structReferences.js

@@ -1,10 +1,10 @@
-import YArray from '../Type/YArray'
-import YMap from '../Type/YMap'
-import YText from '../Type/YText'
-import YXml from '../Type/YXml'
+import YArray from '../Type/YArray.js'
+import YMap from '../Type/YMap.js'
+import YText from '../Type/YText.js'
+import YXml from '../Type/YXml.js'
 
-import ItemJSON from '../Struct/ItemJSON'
-import ItemString from '../Struct/ItemString'
+import ItemJSON from '../Struct/ItemJSON.js'
+import ItemString from '../Struct/ItemString.js'
 
 const structs = new Map()
 const references = new Map()