From 407c2438392f10ac3d7c4e97669f7ed467b21506 Mon Sep 17 00:00:00 2001
From: Kevin Jahns <kevin.jahns@pm.me>
Date: Thu, 14 May 2020 15:31:27 +0200
Subject: [PATCH] add utility setMeta function

---
 src/lib.js                   | 32 ++++++++++++++++++++++++++++++++
 src/plugins/cursor-plugin.js | 20 ++++++++++----------
 src/y-prosemirror.js         |  2 +-
 3 files changed, 43 insertions(+), 11 deletions(-)

diff --git a/src/lib.js b/src/lib.js
index 285fcc7..7054d79 100644
--- a/src/lib.js
+++ b/src/lib.js
@@ -1,7 +1,39 @@
 import { ProsemirrorMapping } from './plugins/sync-plugin.js' // eslint-disable-line
 
 import * as Y from 'yjs'
+// eslint-disable-next-line
+import { EditorView } from 'prosemirror-view'
 import * as error from 'lib0/error.js'
+import * as map from 'lib0/map.js'
+import * as eventloop from 'lib0/eventloop.js'
+
+/**
+ * Is null if no timeout is in progress.
+ * Is defined if a timeout is in progress.
+ * Maps from view
+ * @type {Map<EditorView, Map<any, any>>|null}
+ */
+let viewsToUpdate = null
+
+const updateMetas = () => {
+  const ups = /** @type {Map<EditorView, Map<any, any>>} */ (viewsToUpdate)
+  viewsToUpdate = null
+  ups.forEach((metas, view) => {
+    const tr = view.state.tr
+    metas.forEach((val, key) => {
+      tr.setMeta(key, val)
+    })
+    view.dispatch(tr)
+  })
+}
+
+export const setMeta = (view, key, value) => {
+  if (!viewsToUpdate) {
+    viewsToUpdate = new Map()
+    eventloop.timeout(0, updateMetas)
+  }
+  map.setIfUndefined(viewsToUpdate, view, map.create).set(key, value)
+}
 
 /**
  * Transforms a Prosemirror based absolute position to a Yjs Cursor (relative position in the Yjs model).
diff --git a/src/plugins/cursor-plugin.js b/src/plugins/cursor-plugin.js
index c2e3529..049af19 100644
--- a/src/plugins/cursor-plugin.js
+++ b/src/plugins/cursor-plugin.js
@@ -4,7 +4,7 @@ import { Decoration, DecorationSet } from 'prosemirror-view' // eslint-disable-l
 import { Plugin, PluginKey } from 'prosemirror-state' // eslint-disable-line
 import { Awareness } from 'y-protocols/awareness.js' // eslint-disable-line
 import { ySyncPluginKey } from './sync-plugin.js'
-import { absolutePositionToRelativePosition, relativePositionToAbsolutePosition } from '../lib.js'
+import { absolutePositionToRelativePosition, relativePositionToAbsolutePosition, setMeta } from '../lib.js'
 
 import * as math from 'lib0/math.js'
 
@@ -81,9 +81,10 @@ export const createDecorations = (state, awareness, createCursor) => {
  * @param {Awareness} awareness
  * @param {object} [opts]
  * @param {function(any):HTMLElement} [opts.cursorBuilder]
+ * @param {function(any):any} [opts.getSelection]
  * @return {any}
  */
-export const yCursorPlugin = (awareness, { cursorBuilder = defaultCursorBuilder } = {}) => new Plugin({
+export const yCursorPlugin = (awareness, { cursorBuilder = defaultCursorBuilder, getSelection = state => state.selection } = {}) => new Plugin({
   key: yCursorPluginKey,
   state: {
     init (_, state) {
@@ -105,26 +106,25 @@ export const yCursorPlugin = (awareness, { cursorBuilder = defaultCursorBuilder
   },
   view: view => {
     const awarenessListener = () => {
-      setTimeout(() => {
-        // @ts-ignore
-        if (view.docView) {
-          view.dispatch(view.state.tr.setMeta(yCursorPluginKey, { awarenessUpdated: true }))
-        }
-      })
+      // @ts-ignore
+      if (view.docView) {
+        setMeta(view, yCursorPluginKey, { awarenessUpdated: true })
+      }
     }
     const updateCursorInfo = () => {
       const ystate = ySyncPluginKey.getState(view.state)
       // @note We make implicit checks when checking for the cursor property
       const current = awareness.getLocalState() || {}
       if (view.hasFocus() && ystate.binding !== null) {
+        const selection = getSelection(view.state)
         /**
          * @type {Y.RelativePosition}
          */
-        const anchor = absolutePositionToRelativePosition(view.state.selection.anchor, ystate.type, ystate.binding.mapping)
+        const anchor = absolutePositionToRelativePosition(selection.anchor, ystate.type, ystate.binding.mapping)
         /**
          * @type {Y.RelativePosition}
          */
-        const head = absolutePositionToRelativePosition(view.state.selection.head, ystate.type, ystate.binding.mapping)
+        const head = absolutePositionToRelativePosition(selection.head, ystate.type, ystate.binding.mapping)
         if (current.cursor == null || !Y.compareRelativePositions(Y.createRelativePositionFromJSON(current.cursor.anchor), anchor) || !Y.compareRelativePositions(Y.createRelativePositionFromJSON(current.cursor.head), head)) {
           awareness.setLocalStateField('cursor', {
             anchor, head
diff --git a/src/y-prosemirror.js b/src/y-prosemirror.js
index de63dfb..05fc662 100644
--- a/src/y-prosemirror.js
+++ b/src/y-prosemirror.js
@@ -1,4 +1,4 @@
 export * from './plugins/cursor-plugin.js'
 export * from './plugins/sync-plugin.js'
 export * from './plugins/undo-plugin.js'
-export { absolutePositionToRelativePosition, relativePositionToAbsolutePosition } from './lib.js'
+export { absolutePositionToRelativePosition, relativePositionToAbsolutePosition, setMeta } from './lib.js'