diff --git a/src/utils/IdMap.js b/src/utils/IdMap.js
index 8fbb3fd8..30f848b7 100644
--- a/src/utils/IdMap.js
+++ b/src/utils/IdMap.js
@@ -3,7 +3,7 @@ import {
   findIndexInIdRanges,
   findRangeStartInIdRanges,
   _deleteRangeFromIdSet,
-  DSDecoderV1, DSDecoderV2,  IdSetEncoderV1, IdSetEncoderV2, IdSet, ID, // eslint-disable-line
+  IdSetDecoderV1, IdSetDecoderV2,  IdSetEncoderV1, IdSetEncoderV2, IdSet, ID, // eslint-disable-line
   _insertIntoIdSet,
   _intersectSets,
   createIdSet,
@@ -534,7 +534,7 @@ export const encodeIdMap = idmap => {
 }
 
 /**
- * @param {DSDecoderV1 | DSDecoderV2} decoder
+ * @param {IdSetDecoderV1 | IdSetDecoderV2} decoder
  * @return {IdMap<any>}
  *
  * @private
@@ -596,7 +596,7 @@ export const readIdMap = decoder => {
  * @param {Uint8Array} data
  * @return {IdMap<any>}
  */
-export const decodeIdMap = data => readIdMap(new DSDecoderV2(decoding.createDecoder(data)))
+export const decodeIdMap = data => readIdMap(new IdSetDecoderV2(decoding.createDecoder(data)))
 
 /**
  * @template Attrs
@@ -645,7 +645,7 @@ export const intersectMaps = _intersectSets
  *
  * @template Attrs
  * @param {IdMap<Attrs>} idmap
- * @param {(attr: ContentAttribute<Attrs>) => boolean} predicate
+ * @param {(attr: Array<ContentAttribute<Attrs>>) => boolean} predicate
  * @return {IdMap<Attrs>}
  */
 export const filterIdMap = (idmap, predicate) => {
@@ -656,7 +656,7 @@ export const filterIdMap = (idmap, predicate) => {
      */
     const attrRanges = []
     ranges.getIds().forEach((range) => {
-      if (range.attrs.some(predicate)) {
+      if (predicate(range.attrs)) {
         const rangeCpy = range.copyWith(range.clock, range.len)
         attrRanges.push(rangeCpy)
         rangeCpy.attrs.forEach(attr => {
diff --git a/src/utils/IdSet.js b/src/utils/IdSet.js
index 8b42c6b5..7e73b87e 100644
--- a/src/utils/IdSet.js
+++ b/src/utils/IdSet.js
@@ -7,7 +7,7 @@ import {
   IdMap,
   AttrRanges,
   AttrRange,
-  Skip, AbstractStruct, DSDecoderV1, IdSetEncoderV1, DSDecoderV2, IdSetEncoderV2, Item, GC, StructStore, Transaction, ID // eslint-disable-line
+  Skip, AbstractStruct, IdSetDecoderV1, IdSetEncoderV1, IdSetDecoderV2, IdSetEncoderV2, Item, GC, StructStore, Transaction, ID // eslint-disable-line
 } from '../internals.js'
 
 import * as array from 'lib0/array'
@@ -703,7 +703,7 @@ export const writeIdSet = (encoder, idSet) => {
 }
 
 /**
- * @param {DSDecoderV1 | DSDecoderV2} decoder
+ * @param {IdSetDecoderV1 | IdSetDecoderV2} decoder
  * @return {IdSet}
  *
  * @private
@@ -735,7 +735,7 @@ export const readIdSet = decoder => {
  */
 
 /**
- * @param {DSDecoderV1 | DSDecoderV2} decoder
+ * @param {IdSetDecoderV1 | IdSetDecoderV2} decoder
  * @param {Transaction} transaction
  * @param {StructStore} store
  * @return {Uint8Array<ArrayBuffer>|null} Returns a v2 update containing all deletes that couldn't be applied yet; or null if all deletes were applied successfully.
diff --git a/src/utils/Snapshot.js b/src/utils/Snapshot.js
index c585a9a2..0f57a2fd 100644
--- a/src/utils/Snapshot.js
+++ b/src/utils/Snapshot.js
@@ -15,7 +15,7 @@ import {
   applyUpdateV2,
   LazyStructReader,
   equalIdSets,
-  UpdateDecoderV1, UpdateDecoderV2, IdSetEncoderV1, IdSetEncoderV2, DSDecoderV1, DSDecoderV2, Transaction, Doc, IdSet, Item, // eslint-disable-line
+  UpdateDecoderV1, UpdateDecoderV2, IdSetEncoderV1, IdSetEncoderV2, IdSetDecoderV1, IdSetDecoderV2, Transaction, Doc, IdSet, Item, // eslint-disable-line
   mergeIdSets
 } from '../internals.js'
 
@@ -80,10 +80,10 @@ export const encodeSnapshot = snapshot => encodeSnapshotV2(snapshot, new IdSetEn
 
 /**
  * @param {Uint8Array} buf
- * @param {DSDecoderV1 | DSDecoderV2} [decoder]
+ * @param {IdSetDecoderV1 | IdSetDecoderV2} [decoder]
  * @return {Snapshot}
  */
-export const decodeSnapshotV2 = (buf, decoder = new DSDecoderV2(decoding.createDecoder(buf))) => {
+export const decodeSnapshotV2 = (buf, decoder = new IdSetDecoderV2(decoding.createDecoder(buf))) => {
   return new Snapshot(readIdSet(decoder), readStateVector(decoder))
 }
 
@@ -91,7 +91,7 @@ export const decodeSnapshotV2 = (buf, decoder = new DSDecoderV2(decoding.createD
  * @param {Uint8Array} buf
  * @return {Snapshot}
  */
-export const decodeSnapshot = buf => decodeSnapshotV2(buf, new DSDecoderV1(decoding.createDecoder(buf)))
+export const decodeSnapshot = buf => decodeSnapshotV2(buf, new IdSetDecoderV1(decoding.createDecoder(buf)))
 
 /**
  * @param {IdSet} ds
diff --git a/src/utils/UpdateDecoder.js b/src/utils/UpdateDecoder.js
index 67a38ceb..c269e6ac 100644
--- a/src/utils/UpdateDecoder.js
+++ b/src/utils/UpdateDecoder.js
@@ -4,7 +4,11 @@ import {
   ID, createID
 } from '../internals.js'
 
-export class DSDecoderV1 {
+/**
+ * @typedef {IdSetDecoderV1 | IdSetDecoderV2} IdSetDecoder
+ */
+
+export class IdSetDecoderV1 {
   /**
    * @param {decoding.Decoder} decoder
    */
@@ -31,7 +35,7 @@ export class DSDecoderV1 {
   }
 }
 
-export class UpdateDecoderV1 extends DSDecoderV1 {
+export class UpdateDecoderV1 extends IdSetDecoderV1 {
   /**
    * @return {ID}
    */
@@ -122,7 +126,7 @@ export class UpdateDecoderV1 extends DSDecoderV1 {
   }
 }
 
-export class DSDecoderV2 {
+export class IdSetDecoderV2 {
   /**
    * @param {decoding.Decoder} decoder
    */
@@ -156,7 +160,7 @@ export class DSDecoderV2 {
   }
 }
 
-export class UpdateDecoderV2 extends DSDecoderV2 {
+export class UpdateDecoderV2 extends IdSetDecoderV2 {
   /**
    * @param {decoding.Decoder} decoder
    */
diff --git a/src/utils/encoding.js b/src/utils/encoding.js
index 9d1d951a..fe409a7b 100644
--- a/src/utils/encoding.js
+++ b/src/utils/encoding.js
@@ -26,7 +26,7 @@ import {
   UpdateEncoderV1,
   UpdateEncoderV2,
   IdSetEncoderV2,
-  DSDecoderV1,
+  IdSetDecoderV1,
   IdSetEncoderV1,
   mergeUpdates,
   mergeUpdatesV2,
@@ -36,7 +36,7 @@ import {
   readStructSet,
   removeRangesFromStructSet,
   createIdSet,
-  StructSet, IdSet, DSDecoderV2, Doc, Transaction, GC, Item, StructStore, // eslint-disable-line
+  StructSet, IdSet, IdSetDecoderV2, Doc, Transaction, GC, Item, StructStore, // eslint-disable-line
   createID,
   IdRange
 } from '../internals.js'
@@ -536,7 +536,7 @@ export const encodeStateAsUpdate = (doc, encodedTargetStateVector) => encodeStat
 /**
  * Read state vector from Decoder and return as Map
  *
- * @param {DSDecoderV1 | DSDecoderV2} decoder
+ * @param {IdSetDecoderV1 | IdSetDecoderV2} decoder
  * @return {Map<number,number>} Maps `client` to the number next expected `clock` from that client.
  *
  * @function
@@ -570,7 +570,7 @@ export const readStateVector = decoder => {
  *
  * @function
  */
-export const decodeStateVector = decodedState => readStateVector(new DSDecoderV1(decoding.createDecoder(decodedState)))
+export const decodeStateVector = decodedState => readStateVector(new IdSetDecoderV1(decoding.createDecoder(decodedState)))
 
 /**
  * @param {IdSetEncoderV1 | IdSetEncoderV2} encoder
diff --git a/src/utils/meta.js b/src/utils/meta.js
index 420183c0..e41b2dab 100644
--- a/src/utils/meta.js
+++ b/src/utils/meta.js
@@ -5,6 +5,8 @@
 import * as idmap from './IdMap.js'
 import * as idset from './IdSet.js'
 import { IdSetEncoderV2 } from './UpdateEncoder.js'
+import { IdSetDecoderV2 } from './UpdateDecoder.js'
+import * as decoding from 'lib0/decoding'
 
 /**
  * @typedef {{ inserts: import('./IdSet.js').IdSet, deletes: import('./IdSet.js').IdSet }} ContentIds
@@ -18,7 +20,7 @@ import { IdSetEncoderV2 } from './UpdateEncoder.js'
  * @param {import('./IdSet.js').IdSet} inserts
  * @param {import('./IdSet.js').IdSet} deletes
  */
-export const createContentIds = (inserts, deletes) => ({ inserts, deletes })
+export const createContentIds = (inserts = idset.createIdSet(), deletes = idset.createIdSet()) => ({ inserts, deletes })
 
 /**
  * @param {ContentMap} contentMap
@@ -50,6 +52,31 @@ export const createContentIdsFromDocDiff = (ydocPrev, ydocNext) =>
 export const excludeContentIds = (content, excludeContent) =>
   createContentIds(idset.diffIdSet(content.inserts, excludeContent.inserts), idset.diffIdSet(content.deletes, excludeContent.deletes))
 
+/**
+ * @param {ContentMap} content
+ * @param {ContentIds | ContentMap} excludeContent
+ */
+export const excludeContentMaps = (content, excludeContent) => createContentMap(
+  idmap.diffIdMap(content.inserts, excludeContent.inserts),
+  idmap.diffIdMap(content.deletes, excludeContent.deletes)
+)
+
+/**
+ * @param {Array<ContentMap>} contents
+ */
+export const mergeContentMaps = contents => createContentMap(
+  idmap.mergeIdMaps(contents.map(c => c.inserts)),
+  idmap.mergeIdMaps(contents.map(c => c.deletes))
+)
+
+/**
+ * @param {Array<ContentIds>} contents
+ */
+export const mergeContentIds = contents => createContentIds(
+  idset.mergeIdSets(contents.map(c => c.inserts)),
+  idset.mergeIdSets(contents.map(c => c.deletes))
+)
+
 /**
  * @param {import('./IdMap.js').IdMap<any>} inserts
  * @param {import('./IdMap.js').IdMap<any>} deletes
@@ -78,7 +105,27 @@ export const writeContentIds = (encoder, contentIds) => {
 /**
  * @param {ContentIds} contentIds
  */
-export const encodeContentIds = contentIds => writeContentIds(new IdSetEncoderV2(), contentIds)
+export const encodeContentIds = contentIds => {
+  const encoder = new IdSetEncoderV2()
+  writeContentIds(encoder, contentIds)
+  return encoder.toUint8Array()
+}
+
+/**
+ * @todo this encoding needs to be heavily optimized for production
+ *
+ * @param {import('./UpdateDecoder.js').IdSetDecoder} decoder
+ * @return {ContentIds}
+ */
+export const readContentIds = decoder => createContentIds(
+  idset.readIdSet(decoder),
+  idset.readIdSet(decoder)
+) 
+
+/**
+ * @param {Uint8Array<any>} buf
+ */
+export const decodeContentIds = buf => readContentIds(new IdSetDecoderV2(decoding.createDecoder(buf)))
 
 /**
  * @todo this encoding needs to be heavily optimized for production
@@ -91,7 +138,54 @@ export const writeContentMap = (encoder, contentMap) => {
   idmap.writeIdMap(encoder, contentMap.deletes)
 }
 
+/**
+ * @todo this encoding needs to be heavily optimized for production
+ *
+ * @param {import('./UpdateDecoder.js').IdSetDecoder} decoder
+ * @return {ContentMap} contentMap
+ */
+export const readContentMap = (decoder) => createContentMap(
+  idmap.readIdMap(decoder),
+  idmap.readIdMap(decoder)
+)
+
 /**
  * @param {ContentMap} contentMap
  */
-export const encodeContentMap = contentMap => writeContentMap(new IdSetEncoderV2(), contentMap)
+export const encodeContentMap = contentMap => {
+  const encoder = new IdSetEncoderV2()
+  writeContentMap(encoder, contentMap)
+  return encoder.toUint8Array()
+}
+
+/**
+ * @param {ContentMap} mapA
+ * @param {ContentMap|ContentIds} mapB
+ */
+export const intersectContentMap = (mapA, mapB) => createContentMap(
+  idmap.intersectMaps(mapA.inserts, mapB.inserts),
+  idmap.intersectMaps(mapA.deletes, mapB.deletes)
+)
+
+/**
+ * @param {ContentIds} setA
+ * @param {ContentIds|ContentMap} setB
+ */
+export const intersectContentIds = (setA, setB) => createContentIds(
+  idset.intersectSets(setA.inserts, setB.inserts),
+  idset.intersectSets(setA.deletes, setB.deletes)
+)
+
+/**
+ * @param {Uint8Array<any>} buf
+ */
+export const decodeContentMap = buf => readContentMap(new IdSetDecoderV2(decoding.createDecoder(buf)))
+
+/**
+ * @todo filter by array of content instead
+ * @param {ContentMap} contentMap
+ * @param {(c:Array<idmap.ContentAttribute<any>>)=>boolean} insertPredicate
+ * @param {(c:Array<idmap.ContentAttribute<any>>)=>boolean} deletePredicate
+ */
+export const filterContentMap = (contentMap, insertPredicate, deletePredicate) => createContentMap(idmap.filterIdMap(contentMap.inserts, insertPredicate), idmap.filterIdMap(contentMap.deletes, deletePredicate))
+
diff --git a/tests/attribution.tests.js b/tests/attribution.tests.js
index c46e1a3e..4b48c071 100644
--- a/tests/attribution.tests.js
+++ b/tests/attribution.tests.js
@@ -160,8 +160,8 @@ export const testAttributionSession1 = tc => {
   t.compare(d2, delta.create().insert('a').insert('b', null, { delete: ['0'] }).insert('c', null, { insert: ['1'] }))
 
   const onlyUser0ChangesAttributed = {
-    inserts: Y.filterIdMap(globalAttributions.inserts, attr => attr.name === 'insert' && attr.val === '0'),
-    deletes: Y.filterIdMap(globalAttributions.deletes, attr => attr.name === 'delete' && attr.val === '0')
+    inserts: Y.filterIdMap(globalAttributions.inserts, attrs => attrs.some(attr => attr.name === 'insert' && attr.val === '0')),
+    deletes: Y.filterIdMap(globalAttributions.deletes, attrs => attrs.some(attr => attr.name === 'delete' && attr.val === '0'))
   }
   const amUser0 = new Y.TwosetAttributionManager(onlyUser0ChangesAttributed.inserts, onlyUser0ChangesAttributed.deletes)
   const d3 = text0.toDelta(amUser0)