implement diffDocsToDelta

src/index.js

@@ -120,7 +120,8 @@ export {
   mergeIdMaps,
   readIdMap,
   readIdSet,
-  decodeIdMap
+  decodeIdMap,
+  diffDocsToDelta
 } from './internals.js'
 
 const glo = /** @type {any} */ (typeof globalThis !== 'undefined'

src/internals.js

@@ -18,6 +18,7 @@ export * from './utils/YEvent.js'
 export * from './utils/StructSet.js'
 export * from './utils/IdMap.js'
 export * from './utils/AttributionManager.js'
+export * from './utils/delta-helpers.js'
 
 export * from './types/AbstractType.js'
 export * from './types/YArray.js'

src/types/AbstractType.js

@@ -1351,7 +1351,7 @@ export const typeMapGetDelta = (d, parent, attrsToRender, am, deep, modified, de
   if (attrsToRender == null) {
     parent._map.forEach(renderAttrs)
   } else {
-    attrsToRender.forEach(key => renderAttrs(/** @type {Item} */ (parent._map.get(key)), key))
+    attrsToRender.forEach(key => key != null && renderAttrs(/** @type {Item} */ (parent._map.get(key)), key))
   }
 }
 

src/utils/delta-helpers.js

@@ -0,0 +1,54 @@
+import {
+  createInsertSetFromStructStore,
+  createDeleteSetFromStructStore,
+  createAttributionManagerFromDiff,
+  diffIdSet,
+  mergeIdSets,
+  Item,
+  AbstractType, Doc, // eslint-disable-line
+  iterateStructsByIdSet
+} from '../internals.js'
+import * as delta from 'lib0/delta'
+import * as map from 'lib0/map'
+import * as set from 'lib0/set'
+
+/**
+ * @param {Doc} v1
+ * @param {Doc} v2
+ * @return {delta.DeltaBuilderAny}
+ */
+export const diffDocsToDelta = (v1, v2, { am = createAttributionManagerFromDiff(v1, v2) } = {}) => {
+  const d = delta.create()
+  v2.transact(tr => {
+    v2.share.forEach((type, typename) => {
+      const insertDiff = diffIdSet(createInsertSetFromStructStore(v2.store, false), createInsertSetFromStructStore(v1.store, false))
+      const deleteDiff = diffIdSet(createDeleteSetFromStructStore(v2.store), createDeleteSetFromStructStore(v1.store))
+      // don't render items that have been inserted and then deleted
+      const insertsOnly = diffIdSet(insertDiff, deleteDiff)
+      const deletesOnly = diffIdSet(deleteDiff, insertDiff)
+      const itemsToRender = mergeIdSets([insertsOnly, deleteDiff])
+      /**
+       * @type {Map<AbstractType, Set<string|null>>}
+       */
+      const changedTypes = new Map()
+      iterateStructsByIdSet(tr, itemsToRender, /** @param {any} item */ item => {
+        while (item instanceof Item) {
+          const parent = /** @type {AbstractType} */ (item.parent)
+          const conf = map.setIfUndefined(changedTypes, parent, set.create)
+          if (conf.has(item.parentSub)) break // has already been marked as modified
+          conf.add(item.parentSub)
+          item = parent._item
+        }
+      })
+      const typeConf = changedTypes.get(type)
+      if (typeConf) {
+        // @ts-ignore
+        const shareDelta = type.getContent(am, {
+          itemsToRender, retainDeletes: true, renderAttrs: /** @type {Set<string>} */ (changedTypes.get(type)), renderChildren: typeConf.has(null), deletedItems: deletesOnly, modified: changedTypes, deep: true
+        })
+        d.update(typename, shareDelta)
+      }
+    })
+  })
+  return d
+}

tests/attribution.tests.js

@@ -86,3 +86,25 @@ export const testInsertionsIntoAttributedContent = _tc => {
   ytext.applyDelta(delta.text().retain(9).insert('l'), am)
   t.assert(ytext.toString() === 'hello world')
 }
+
+export const testYdocDiff = () => {
+  const ydocStart = new Y.Doc()
+  ydocStart.getText('text').insert(0, 'hello')
+  ydocStart.getArray('array').insert(0, [1, 2, 3])
+  ydocStart.getMap('map').set('k', 42)
+  ydocStart.getMap('map').set('nested', new Y.Array())
+  const ydocUpdated = Y.cloneDoc(ydocStart)
+  ydocUpdated.getText('text').insert(5, ' world')
+  ydocUpdated.getArray('array').insert(1, ['x'])
+  ydocUpdated.getMap('map').set('newk', 42)
+  ydocUpdated.getMap('map').get('nested').insert(0, [1])
+  // @todo add custom attribution
+  const d = Y.diffDocsToDelta(ydocStart, ydocUpdated)
+  t.compare(d, delta.create()
+    .update('text', delta.create().retain(5).insert('world'))
+    .update('array', delta.create().retain(1).insert(['x']))
+    .update('map', delta.create().set('newk', 42).update('nested', delta.create().insert([1])))
+  )
+  console.log(d.toJSON())
+  debugger
+}