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434 lines
17 KiB
434 lines
17 KiB
import RopeSequence from 'rope-sequence';
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import { Mapping } from 'prosemirror-transform';
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import { PluginKey, Plugin } from 'prosemirror-state';
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// ProseMirror's history isn't simply a way to roll back to a previous
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// state, because ProseMirror supports applying changes without adding
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// them to the history (for example during collaboration).
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//
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// To this end, each 'Branch' (one for the undo history and one for
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// the redo history) keeps an array of 'Items', which can optionally
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// hold a step (an actual undoable change), and always hold a position
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// map (which is needed to move changes below them to apply to the
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// current document).
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//
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// An item that has both a step and a selection bookmark is the start
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// of an 'event' — a group of changes that will be undone or redone at
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// once. (It stores only the bookmark, since that way we don't have to
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// provide a document until the selection is actually applied, which
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// is useful when compressing.)
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// Used to schedule history compression
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const max_empty_items = 500;
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class Branch {
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constructor(items, eventCount) {
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this.items = items;
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this.eventCount = eventCount;
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}
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// Pop the latest event off the branch's history and apply it
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// to a document transform.
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popEvent(state, preserveItems) {
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if (this.eventCount == 0)
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return null;
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let end = this.items.length;
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for (;; end--) {
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let next = this.items.get(end - 1);
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if (next.selection) {
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--end;
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break;
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}
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}
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let remap, mapFrom;
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if (preserveItems) {
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remap = this.remapping(end, this.items.length);
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mapFrom = remap.maps.length;
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}
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let transform = state.tr;
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let selection, remaining;
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let addAfter = [], addBefore = [];
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this.items.forEach((item, i) => {
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if (!item.step) {
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if (!remap) {
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remap = this.remapping(end, i + 1);
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mapFrom = remap.maps.length;
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}
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mapFrom--;
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addBefore.push(item);
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return;
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}
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if (remap) {
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addBefore.push(new Item(item.map));
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let step = item.step.map(remap.slice(mapFrom)), map;
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if (step && transform.maybeStep(step).doc) {
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map = transform.mapping.maps[transform.mapping.maps.length - 1];
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addAfter.push(new Item(map, undefined, undefined, addAfter.length + addBefore.length));
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}
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mapFrom--;
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if (map)
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remap.appendMap(map, mapFrom);
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}
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else {
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transform.maybeStep(item.step);
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}
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if (item.selection) {
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selection = remap ? item.selection.map(remap.slice(mapFrom)) : item.selection;
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remaining = new Branch(this.items.slice(0, end).append(addBefore.reverse().concat(addAfter)), this.eventCount - 1);
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return false;
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}
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}, this.items.length, 0);
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return { remaining: remaining, transform, selection: selection };
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}
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// Create a new branch with the given transform added.
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addTransform(transform, selection, histOptions, preserveItems) {
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let newItems = [], eventCount = this.eventCount;
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let oldItems = this.items, lastItem = !preserveItems && oldItems.length ? oldItems.get(oldItems.length - 1) : null;
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for (let i = 0; i < transform.steps.length; i++) {
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let step = transform.steps[i].invert(transform.docs[i]);
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let item = new Item(transform.mapping.maps[i], step, selection), merged;
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if (merged = lastItem && lastItem.merge(item)) {
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item = merged;
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if (i)
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newItems.pop();
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else
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oldItems = oldItems.slice(0, oldItems.length - 1);
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}
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newItems.push(item);
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if (selection) {
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eventCount++;
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selection = undefined;
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}
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if (!preserveItems)
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lastItem = item;
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}
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let overflow = eventCount - histOptions.depth;
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if (overflow > DEPTH_OVERFLOW) {
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oldItems = cutOffEvents(oldItems, overflow);
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eventCount -= overflow;
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}
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return new Branch(oldItems.append(newItems), eventCount);
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}
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remapping(from, to) {
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let maps = new Mapping;
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this.items.forEach((item, i) => {
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let mirrorPos = item.mirrorOffset != null && i - item.mirrorOffset >= from
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? maps.maps.length - item.mirrorOffset : undefined;
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maps.appendMap(item.map, mirrorPos);
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}, from, to);
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return maps;
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}
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addMaps(array) {
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if (this.eventCount == 0)
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return this;
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return new Branch(this.items.append(array.map(map => new Item(map))), this.eventCount);
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}
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// When the collab module receives remote changes, the history has
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// to know about those, so that it can adjust the steps that were
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// rebased on top of the remote changes, and include the position
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// maps for the remote changes in its array of items.
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rebased(rebasedTransform, rebasedCount) {
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if (!this.eventCount)
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return this;
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let rebasedItems = [], start = Math.max(0, this.items.length - rebasedCount);
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let mapping = rebasedTransform.mapping;
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let newUntil = rebasedTransform.steps.length;
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let eventCount = this.eventCount;
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this.items.forEach(item => { if (item.selection)
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eventCount--; }, start);
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let iRebased = rebasedCount;
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this.items.forEach(item => {
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let pos = mapping.getMirror(--iRebased);
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if (pos == null)
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return;
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newUntil = Math.min(newUntil, pos);
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let map = mapping.maps[pos];
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if (item.step) {
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let step = rebasedTransform.steps[pos].invert(rebasedTransform.docs[pos]);
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let selection = item.selection && item.selection.map(mapping.slice(iRebased + 1, pos));
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if (selection)
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eventCount++;
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rebasedItems.push(new Item(map, step, selection));
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}
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else {
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rebasedItems.push(new Item(map));
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}
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}, start);
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let newMaps = [];
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for (let i = rebasedCount; i < newUntil; i++)
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newMaps.push(new Item(mapping.maps[i]));
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let items = this.items.slice(0, start).append(newMaps).append(rebasedItems);
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let branch = new Branch(items, eventCount);
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if (branch.emptyItemCount() > max_empty_items)
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branch = branch.compress(this.items.length - rebasedItems.length);
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return branch;
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}
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emptyItemCount() {
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let count = 0;
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this.items.forEach(item => { if (!item.step)
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count++; });
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return count;
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}
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// Compressing a branch means rewriting it to push the air (map-only
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// items) out. During collaboration, these naturally accumulate
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// because each remote change adds one. The `upto` argument is used
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// to ensure that only the items below a given level are compressed,
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// because `rebased` relies on a clean, untouched set of items in
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// order to associate old items with rebased steps.
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compress(upto = this.items.length) {
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let remap = this.remapping(0, upto), mapFrom = remap.maps.length;
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let items = [], events = 0;
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this.items.forEach((item, i) => {
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if (i >= upto) {
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items.push(item);
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if (item.selection)
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events++;
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}
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else if (item.step) {
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let step = item.step.map(remap.slice(mapFrom)), map = step && step.getMap();
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mapFrom--;
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if (map)
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remap.appendMap(map, mapFrom);
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if (step) {
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let selection = item.selection && item.selection.map(remap.slice(mapFrom));
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if (selection)
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events++;
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let newItem = new Item(map.invert(), step, selection), merged, last = items.length - 1;
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if (merged = items.length && items[last].merge(newItem))
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items[last] = merged;
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else
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items.push(newItem);
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}
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}
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else if (item.map) {
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mapFrom--;
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}
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}, this.items.length, 0);
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return new Branch(RopeSequence.from(items.reverse()), events);
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}
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}
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Branch.empty = new Branch(RopeSequence.empty, 0);
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function cutOffEvents(items, n) {
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let cutPoint;
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items.forEach((item, i) => {
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if (item.selection && (n-- == 0)) {
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cutPoint = i;
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return false;
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}
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});
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return items.slice(cutPoint);
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}
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class Item {
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constructor(
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// The (forward) step map for this item.
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map,
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// The inverted step
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step,
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// If this is non-null, this item is the start of a group, and
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// this selection is the starting selection for the group (the one
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// that was active before the first step was applied)
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selection,
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// If this item is the inverse of a previous mapping on the stack,
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// this points at the inverse's offset
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mirrorOffset) {
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this.map = map;
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this.step = step;
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this.selection = selection;
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this.mirrorOffset = mirrorOffset;
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}
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merge(other) {
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if (this.step && other.step && !other.selection) {
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let step = other.step.merge(this.step);
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if (step)
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return new Item(step.getMap().invert(), step, this.selection);
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}
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}
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}
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// The value of the state field that tracks undo/redo history for that
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// state. Will be stored in the plugin state when the history plugin
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// is active.
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class HistoryState {
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constructor(done, undone, prevRanges, prevTime) {
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this.done = done;
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this.undone = undone;
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this.prevRanges = prevRanges;
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this.prevTime = prevTime;
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}
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}
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const DEPTH_OVERFLOW = 20;
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// Record a transformation in undo history.
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function applyTransaction(history, state, tr, options) {
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let historyTr = tr.getMeta(historyKey), rebased;
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if (historyTr)
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return historyTr.historyState;
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if (tr.getMeta(closeHistoryKey))
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history = new HistoryState(history.done, history.undone, null, 0);
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let appended = tr.getMeta("appendedTransaction");
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if (tr.steps.length == 0) {
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return history;
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}
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else if (appended && appended.getMeta(historyKey)) {
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if (appended.getMeta(historyKey).redo)
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return new HistoryState(history.done.addTransform(tr, undefined, options, mustPreserveItems(state)), history.undone, rangesFor(tr.mapping.maps[tr.steps.length - 1]), history.prevTime);
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else
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return new HistoryState(history.done, history.undone.addTransform(tr, undefined, options, mustPreserveItems(state)), null, history.prevTime);
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}
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else if (tr.getMeta("addToHistory") !== false && !(appended && appended.getMeta("addToHistory") === false)) {
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// Group transforms that occur in quick succession into one event.
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let newGroup = history.prevTime == 0 || !appended && (history.prevTime < (tr.time || 0) - options.newGroupDelay ||
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!isAdjacentTo(tr, history.prevRanges));
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let prevRanges = appended ? mapRanges(history.prevRanges, tr.mapping) : rangesFor(tr.mapping.maps[tr.steps.length - 1]);
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return new HistoryState(history.done.addTransform(tr, newGroup ? state.selection.getBookmark() : undefined, options, mustPreserveItems(state)), Branch.empty, prevRanges, tr.time);
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}
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else if (rebased = tr.getMeta("rebased")) {
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// Used by the collab module to tell the history that some of its
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// content has been rebased.
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return new HistoryState(history.done.rebased(tr, rebased), history.undone.rebased(tr, rebased), mapRanges(history.prevRanges, tr.mapping), history.prevTime);
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}
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else {
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return new HistoryState(history.done.addMaps(tr.mapping.maps), history.undone.addMaps(tr.mapping.maps), mapRanges(history.prevRanges, tr.mapping), history.prevTime);
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}
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}
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function isAdjacentTo(transform, prevRanges) {
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if (!prevRanges)
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return false;
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if (!transform.docChanged)
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return true;
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let adjacent = false;
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transform.mapping.maps[0].forEach((start, end) => {
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for (let i = 0; i < prevRanges.length; i += 2)
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if (start <= prevRanges[i + 1] && end >= prevRanges[i])
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adjacent = true;
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});
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return adjacent;
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}
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function rangesFor(map) {
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let result = [];
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map.forEach((_from, _to, from, to) => result.push(from, to));
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return result;
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}
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function mapRanges(ranges, mapping) {
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if (!ranges)
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return null;
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let result = [];
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for (let i = 0; i < ranges.length; i += 2) {
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let from = mapping.map(ranges[i], 1), to = mapping.map(ranges[i + 1], -1);
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if (from <= to)
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result.push(from, to);
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}
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return result;
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}
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// Apply the latest event from one branch to the document and shift the event
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// onto the other branch.
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function histTransaction(history, state, dispatch, redo) {
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let preserveItems = mustPreserveItems(state);
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let histOptions = historyKey.get(state).spec.config;
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let pop = (redo ? history.undone : history.done).popEvent(state, preserveItems);
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if (!pop)
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return;
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let selection = pop.selection.resolve(pop.transform.doc);
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let added = (redo ? history.done : history.undone).addTransform(pop.transform, state.selection.getBookmark(), histOptions, preserveItems);
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let newHist = new HistoryState(redo ? added : pop.remaining, redo ? pop.remaining : added, null, 0);
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dispatch(pop.transform.setSelection(selection).setMeta(historyKey, { redo, historyState: newHist }).scrollIntoView());
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}
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let cachedPreserveItems = false, cachedPreserveItemsPlugins = null;
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// Check whether any plugin in the given state has a
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// `historyPreserveItems` property in its spec, in which case we must
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// preserve steps exactly as they came in, so that they can be
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// rebased.
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function mustPreserveItems(state) {
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let plugins = state.plugins;
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if (cachedPreserveItemsPlugins != plugins) {
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cachedPreserveItems = false;
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cachedPreserveItemsPlugins = plugins;
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for (let i = 0; i < plugins.length; i++)
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if (plugins[i].spec.historyPreserveItems) {
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cachedPreserveItems = true;
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break;
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}
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}
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return cachedPreserveItems;
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}
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/**
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Set a flag on the given transaction that will prevent further steps
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from being appended to an existing history event (so that they
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require a separate undo command to undo).
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*/
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function closeHistory(tr) {
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return tr.setMeta(closeHistoryKey, true);
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}
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const historyKey = new PluginKey("history");
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const closeHistoryKey = new PluginKey("closeHistory");
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/**
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Returns a plugin that enables the undo history for an editor. The
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plugin will track undo and redo stacks, which can be used with the
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[`undo`](https://prosemirror.net/docs/ref/#history.undo) and [`redo`](https://prosemirror.net/docs/ref/#history.redo) commands.
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You can set an `"addToHistory"` [metadata
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property](https://prosemirror.net/docs/ref/#state.Transaction.setMeta) of `false` on a transaction
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to prevent it from being rolled back by undo.
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*/
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function history(config = {}) {
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config = { depth: config.depth || 100,
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newGroupDelay: config.newGroupDelay || 500 };
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return new Plugin({
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key: historyKey,
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state: {
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init() {
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return new HistoryState(Branch.empty, Branch.empty, null, 0);
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},
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apply(tr, hist, state) {
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return applyTransaction(hist, state, tr, config);
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}
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},
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config,
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props: {
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handleDOMEvents: {
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beforeinput(view, e) {
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let inputType = e.inputType;
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let command = inputType == "historyUndo" ? undo : inputType == "historyRedo" ? redo : null;
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if (!command)
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return false;
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e.preventDefault();
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return command(view.state, view.dispatch);
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}
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}
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}
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});
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}
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/**
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A command function that undoes the last change, if any.
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*/
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const undo = (state, dispatch) => {
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let hist = historyKey.getState(state);
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if (!hist || hist.done.eventCount == 0)
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return false;
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if (dispatch)
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histTransaction(hist, state, dispatch, false);
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return true;
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};
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/**
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A command function that redoes the last undone change, if any.
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*/
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const redo = (state, dispatch) => {
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let hist = historyKey.getState(state);
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if (!hist || hist.undone.eventCount == 0)
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return false;
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if (dispatch)
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histTransaction(hist, state, dispatch, true);
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return true;
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};
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/**
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The amount of undoable events available in a given state.
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*/
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function undoDepth(state) {
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let hist = historyKey.getState(state);
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return hist ? hist.done.eventCount : 0;
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}
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/**
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The amount of redoable events available in a given editor state.
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*/
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function redoDepth(state) {
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let hist = historyKey.getState(state);
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return hist ? hist.undone.eventCount : 0;
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}
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export { closeHistory, history, redo, redoDepth, undo, undoDepth };
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