Replace setGlobalMetadata with changeMetadata function

packages/automerge-repo/src/DocHandle.ts

@@ -41,9 +41,7 @@ export class DocHandle<T> //
   #machine: DocHandleXstateMachine<T>
   #timeoutDelay: number
   #remoteHeads: Record<StorageId, A.Heads> = {}
-
-  // Reference to global meta data that is set on the repo to be attached to each change
-  #globalMetadataRef?: ChangeMetadataRef
+  #changeMetadata: ChangeMetadataFunction
 
   /** The URL of this document
    *
@@ -60,12 +58,12 @@ export class DocHandle<T> //
     {
       isNew = false,
       timeoutDelay = 60_000,
-      globalMetadataRef,
+      changeMetadata = () => undefined,
     }: DocHandleOptions = {}
   ) {
     super()
     this.#timeoutDelay = timeoutDelay
-    this.#globalMetadataRef = globalMetadataRef
+    this.#changeMetadata = changeMetadata
     this.#log = debug(`automerge-repo:dochandle:${this.documentId.slice(0, 5)}`)
 
     // initial doc
@@ -364,7 +362,7 @@ export class DocHandle<T> //
             doc,
             optionsWithGlobalMetadata(
               options,
-              this.#globalMetadataRef?.current ?? {}
+              this.#changeMetadata(this.documentId) ?? {}
             ),
             callback
           )
@@ -396,7 +394,7 @@ export class DocHandle<T> //
             heads,
             optionsWithGlobalMetadata(
               options,
-              this.#globalMetadataRef?.current ?? {}
+              this.#changeMetadata(this.documentId) ?? {}
             ),
             callback
           )
@@ -502,7 +500,7 @@ function optionsWithGlobalMetadata<T>(
 export interface DocHandleOptions {
   isNew?: boolean
   timeoutDelay?: number
-  globalMetadataRef?: ChangeMetadataRef
+  changeMetadata?: ChangeMetadataFunction
 }
 
 // todo: remove this type once we have real metadata on changes in automerge
@@ -514,9 +512,16 @@ export interface DocHandleChangeOptions<T> {
 }
 
 export type ChangeMetadata = Record<string, number | string | boolean>
-export interface ChangeMetadataRef {
-  current: ChangeMetadata
-}
+
+/** A function that defines default meta data for each change on the handle
+ *
+ * @remarks
+ * This function can be defined globally on the {@link Repo} and is passed down to all {@link DocHandle}.
+ * The metadata can be override by explicitly passing metadata in {@link DocHandle.change} or {@link DocHandle.changeAt}.
+ * */
+export type ChangeMetadataFunction = (
+  documentId: DocumentId
+) => ChangeMetadata | undefined
 
 export interface DocHandleMessagePayload {
   destinationId: PeerId

packages/automerge-repo/src/Repo.ts

@@ -10,7 +10,7 @@ import {
   DocHandle,
   DocHandleEncodedChangePayload,
   ChangeMetadata,
-  ChangeMetadataRef,
+  ChangeMetadataFunction,
 } from "./DocHandle.js"
 import { RemoteHeadsSubscriptions } from "./RemoteHeadsSubscriptions.js"
 import { headsAreSame } from "./helpers/headsAreSame.js"
@@ -60,7 +60,7 @@ export class Repo extends EventEmitter<RepoEvents> {
   #remoteHeadsSubscriptions = new RemoteHeadsSubscriptions()
   #remoteHeadsGossipingEnabled = false
 
-  #globalMetadataRef: ChangeMetadataRef = { current: {} }
+  #changeMetadata: ChangeMetadataFunction
 
   constructor({
     storage,
@@ -69,11 +69,13 @@ export class Repo extends EventEmitter<RepoEvents> {
     sharePolicy,
     isEphemeral = storage === undefined,
     enableRemoteHeadsGossiping = false,
+    changeMetadata = () => undefined,
   }: RepoConfig) {
     super()
     this.#remoteHeadsGossipingEnabled = enableRemoteHeadsGossiping
     this.#log = debug(`automerge-repo:repo`)
     this.sharePolicy = sharePolicy ?? this.sharePolicy
+    this.#changeMetadata = changeMetadata
 
     // DOC COLLECTION
 
@@ -340,7 +342,7 @@ export class Repo extends EventEmitter<RepoEvents> {
     if (!documentId) throw new Error(`Invalid documentId ${documentId}`)
     const handle = new DocHandle<T>(documentId, {
       isNew,
-      globalMetadataRef: this.#globalMetadataRef,
+      changeMetadata: this.#changeMetadata,
     })
     this.#handleCache[documentId] = handle
     return handle
@@ -356,11 +358,6 @@ export class Repo extends EventEmitter<RepoEvents> {
     return this.#synchronizer.peers
   }
 
-  /** Set meta data that will be attached to each change that is created through a handle from this repo */
-  setGlobalMetadata(metadata: ChangeMetadata) {
-    this.#globalMetadataRef.current = metadata
-  }
-
   getStorageIdOfPeer(peerId: PeerId): StorageId | undefined {
     return this.peerMetadataByPeerId[peerId]?.storageId
   }
@@ -547,6 +544,12 @@ export interface RepoConfig {
    */
   sharePolicy?: SharePolicy
 
+  /**
+   * Define default meta data that is added to each change made through the repo.
+   * This function is called inside of {@link DocHandle} on each change.
+   */
+  changeMetadata?: ChangeMetadataFunction
+
   /**
    * Whether to enable the experimental remote heads gossiping feature
    */

packages/automerge-repo/test/DocHandle.test.ts

@@ -307,7 +307,13 @@ describe("DocHandle", () => {
     it("should allow to pass in a reference to global metadata", () => {
       const handle = new DocHandle<TestDoc>(TEST_ID, {
         isNew: true,
-        globalMetadataRef: { current: { author: "bob" } },
+        changeMetadata: documentId => {
+          assert.equal(documentId, handle.documentId)
+
+          return {
+            author: "bob",
+          }
+        },
       })
 
       const doc1 = handle.docSync()
@@ -333,7 +339,13 @@ describe("DocHandle", () => {
     it("should allow to add additional local metadata with", () => {
       const handle = new DocHandle<TestDoc>(TEST_ID, {
         isNew: true,
-        globalMetadataRef: { current: { author: "bob" } },
+        changeMetadata: documentId => {
+          assert.equal(documentId, handle.documentId)
+
+          return {
+            author: "bob",
+          }
+        },
       })
 
       const doc1 = handle.docSync()
@@ -372,7 +384,13 @@ describe("DocHandle", () => {
     it("should allow to override global data with change", () => {
       const handle = new DocHandle<TestDoc>(TEST_ID, {
         isNew: true,
-        globalMetadataRef: { current: { author: "bob" } },
+        changeMetadata: documentId => {
+          assert.equal(documentId, handle.documentId)
+
+          return {
+            author: "bob",
+          }
+        },
       })
 
       const doc1 = handle.docSync()

packages/automerge-repo/test/Repo.test.ts

@@ -31,6 +31,7 @@ import {
 import { getRandomItem } from "./helpers/getRandomItem.js"
 import { TestDoc } from "./types.js"
 import { StorageId } from "../src/storage/types.js"
+import { ChangeMetadataFunction } from "../src/DocHandle.js"
 
 describe("Repo", () => {
   describe("constructor", () => {
@@ -43,13 +44,20 @@ describe("Repo", () => {
   })
 
   describe("local only", () => {
-    const setup = ({ startReady = true } = {}) => {
+    const setup = ({
+      startReady = true,
+      changeMetadata,
+    }: {
+      startReady?: boolean
+      changeMetadata?: ChangeMetadataFunction
+    } = {}) => {
       const storageAdapter = new DummyStorageAdapter()
       const networkAdapter = new DummyNetworkAdapter({ startReady })
 
       const repo = new Repo({
         storage: storageAdapter,
         network: [networkAdapter],
+        changeMetadata,
       })
       return { repo, storageAdapter, networkAdapter }
     }
@@ -453,14 +461,19 @@ describe("Repo", () => {
       }).toThrow()
     })
 
-    it("can set global change metadata", () => {
-      const { repo } = setup()
+    it("can set change metadata function", () => {
+      const { repo } = setup({
+        changeMetadata: documentId => {
+          assert.equal(documentId, handle.documentId)
+
+          return { author: "bob" }
+        },
+      })
 
       const handle = repo.create<TestDoc>()
 
       const doc1 = handle.docSync()
 
-      repo.setGlobalMetadata({ author: "bob" })
       handle.change(doc => {
         doc.foo = "bar"
       })