mirror of
https://github.com/ether/etherpad-lite.git
synced 2025-04-22 00:16:15 -04:00
lint: undomodule
This commit is contained in:
John McLear
Richard Hansen
parent
89bcfa2b4a
commit
f72ce463ef
1 changed files with 57 additions and 59 deletions
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@ -1,3 +1,5 @@
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'use strict';
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/**
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* This code is mostly from the old Etherpad. Please help us to comment this code.
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* This helps other people to understand this code better and helps them to improve it.
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@ -23,8 +25,8 @@
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const Changeset = require('./Changeset');
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const _ = require('./underscore');
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var undoModule = (function () {
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const stack = (function () {
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const undoModule = (() => {
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const stack = (() => {
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const stackElements = [];
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// two types of stackElements:
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// 1) { elementType: UNDOABLE_EVENT, eventType: "anything", [backset: <changeset>,]
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@ -36,7 +38,7 @@ var undoModule = (function () {
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const UNDOABLE_EVENT = 'undoableEvent';
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const EXTERNAL_CHANGE = 'externalChange';
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function clearStack() {
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const clearStack = () => {
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stackElements.length = 0;
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stackElements.push(
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{
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@ -44,22 +46,23 @@ var undoModule = (function () {
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eventType: 'bottom',
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});
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numUndoableEvents = 1;
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}
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};
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clearStack();
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function pushEvent(event) {
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const pushEvent = (event) => {
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const e = _.extend(
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{}, event);
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e.elementType = UNDOABLE_EVENT;
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stackElements.push(e);
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numUndoableEvents++;
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// dmesg("pushEvent backset: "+event.backset);
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}
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};
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function pushExternalChange(cs) {
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const pushExternalChange = (cs) => {
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const idx = stackElements.length - 1;
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if (stackElements[idx].elementType == EXTERNAL_CHANGE) {
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stackElements[idx].changeset = Changeset.compose(stackElements[idx].changeset, cs, getAPool());
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if (stackElements[idx].elementType === EXTERNAL_CHANGE) {
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stackElements[idx].changeset =
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Changeset.compose(stackElements[idx].changeset, cs, getAPool());
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} else {
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stackElements.push(
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{
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@ -67,14 +70,14 @@ var undoModule = (function () {
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changeset: cs,
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});
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}
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}
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};
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function _exposeEvent(nthFromTop) {
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const _exposeEvent = (nthFromTop) => {
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// precond: 0 <= nthFromTop < numUndoableEvents
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const targetIndex = stackElements.length - 1 - nthFromTop;
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let idx = stackElements.length - 1;
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while (idx > targetIndex || stackElements[idx].elementType == EXTERNAL_CHANGE) {
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if (stackElements[idx].elementType == EXTERNAL_CHANGE) {
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while (idx > targetIndex || stackElements[idx].elementType === EXTERNAL_CHANGE) {
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if (stackElements[idx].elementType === EXTERNAL_CHANGE) {
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const ex = stackElements[idx];
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const un = stackElements[idx - 1];
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if (un.backset) {
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@ -86,15 +89,16 @@ var undoModule = (function () {
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const newSel = Changeset.characterRangeFollow(excs, un.selStart, un.selEnd);
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un.selStart = newSel[0];
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un.selEnd = newSel[1];
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if (un.selStart == un.selEnd) {
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if (un.selStart === un.selEnd) {
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un.selFocusAtStart = false;
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}
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}
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}
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stackElements[idx - 1] = ex;
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stackElements[idx] = un;
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if (idx >= 2 && stackElements[idx - 2].elementType == EXTERNAL_CHANGE) {
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ex.changeset = Changeset.compose(stackElements[idx - 2].changeset, ex.changeset, getAPool());
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if (idx >= 2 && stackElements[idx - 2].elementType === EXTERNAL_CHANGE) {
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ex.changeset =
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Changeset.compose(stackElements[idx - 2].changeset, ex.changeset, getAPool());
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stackElements.splice(idx - 2, 1);
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idx--;
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}
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@ -102,24 +106,22 @@ var undoModule = (function () {
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idx--;
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}
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}
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}
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};
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function getNthFromTop(n) {
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const getNthFromTop = (n) => {
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// precond: 0 <= n < numEvents()
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_exposeEvent(n);
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return stackElements[stackElements.length - 1 - n];
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}
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};
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function numEvents() {
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return numUndoableEvents;
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}
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const numEvents = () => numUndoableEvents;
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function popEvent() {
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const popEvent = () => {
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// precond: numEvents() > 0
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_exposeEvent(0);
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numUndoableEvents--;
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return stackElements.pop();
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}
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};
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return {
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numEvents,
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@ -134,12 +136,12 @@ var undoModule = (function () {
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// invariant: stack always has at least one undoable event
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let undoPtr = 0; // zero-index from top of stack, 0 == top
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function clearHistory() {
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const clearHistory = () => {
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stack.clearStack();
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undoPtr = 0;
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}
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};
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function _charOccurrences(str, c) {
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const _charOccurrences = (str, c) => {
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let i = 0;
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let count = 0;
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while (i >= 0 && i < str.length) {
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@ -150,13 +152,11 @@ var undoModule = (function () {
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}
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}
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return count;
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}
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};
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function _opcodeOccurrences(cs, opcode) {
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return _charOccurrences(Changeset.unpack(cs).ops, opcode);
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}
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const _opcodeOccurrences = (cs, opcode) => _charOccurrences(Changeset.unpack(cs).ops, opcode);
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function _mergeChangesets(cs1, cs2) {
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const _mergeChangesets = (cs1, cs2) => {
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if (!cs1) return cs2;
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if (!cs2) return cs1;
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@ -170,40 +170,40 @@ var undoModule = (function () {
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const plusCount2 = _opcodeOccurrences(cs2, '+');
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const minusCount1 = _opcodeOccurrences(cs1, '-');
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const minusCount2 = _opcodeOccurrences(cs2, '-');
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if (plusCount1 == 1 && plusCount2 == 1 && minusCount1 == 0 && minusCount2 == 0) {
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var merge = Changeset.compose(cs1, cs2, getAPool());
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var plusCount3 = _opcodeOccurrences(merge, '+');
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var minusCount3 = _opcodeOccurrences(merge, '-');
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if (plusCount3 == 1 && minusCount3 == 0) {
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if (plusCount1 === 1 && plusCount2 === 1 && minusCount1 === 0 && minusCount2 === 0) {
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const merge = Changeset.compose(cs1, cs2, getAPool());
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const plusCount3 = _opcodeOccurrences(merge, '+');
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const minusCount3 = _opcodeOccurrences(merge, '-');
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if (plusCount3 === 1 && minusCount3 === 0) {
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return merge;
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}
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} else if (plusCount1 == 0 && plusCount2 == 0 && minusCount1 == 1 && minusCount2 == 1) {
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var merge = Changeset.compose(cs1, cs2, getAPool());
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var plusCount3 = _opcodeOccurrences(merge, '+');
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var minusCount3 = _opcodeOccurrences(merge, '-');
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if (plusCount3 == 0 && minusCount3 == 1) {
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} else if (plusCount1 === 0 && plusCount2 === 0 && minusCount1 === 1 && minusCount2 === 1) {
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const merge = Changeset.compose(cs1, cs2, getAPool());
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const plusCount3 = _opcodeOccurrences(merge, '+');
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const minusCount3 = _opcodeOccurrences(merge, '-');
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if (plusCount3 === 0 && minusCount3 === 1) {
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return merge;
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}
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}
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return null;
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}
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};
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function reportEvent(event) {
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const reportEvent = (event) => {
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const topEvent = stack.getNthFromTop(0);
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function applySelectionToTop() {
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const applySelectionToTop = () => {
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if ((typeof event.selStart) === 'number') {
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topEvent.selStart = event.selStart;
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topEvent.selEnd = event.selEnd;
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topEvent.selFocusAtStart = event.selFocusAtStart;
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}
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}
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};
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if ((!event.backset) || Changeset.isIdentity(event.backset)) {
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applySelectionToTop();
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} else {
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let merged = false;
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if (topEvent.eventType == event.eventType) {
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if (topEvent.eventType === event.eventType) {
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const merge = _mergeChangesets(event.backset, topEvent.backset);
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if (merge) {
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topEvent.backset = merge;
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@ -225,15 +225,15 @@ var undoModule = (function () {
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}
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undoPtr = 0;
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}
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}
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};
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function reportExternalChange(changeset) {
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const reportExternalChange = (changeset) => {
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if (changeset && !Changeset.isIdentity(changeset)) {
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stack.pushExternalChange(changeset);
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}
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}
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};
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function _getSelectionInfo(event) {
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const _getSelectionInfo = (event) => {
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if ((typeof event.selStart) !== 'number') {
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return null;
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} else {
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@ -243,7 +243,7 @@ var undoModule = (function () {
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selFocusAtStart: event.selFocusAtStart,
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};
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}
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}
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};
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// For "undo" and "redo", the change event must be returned
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// by eventFunc and NOT reported through the normal mechanism.
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@ -251,7 +251,7 @@ var undoModule = (function () {
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// or can be called with no arguments to mean that no undo is possible.
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// "eventFunc" will be called exactly once.
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function performUndo(eventFunc) {
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const performUndo = (eventFunc) => {
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if (undoPtr < stack.numEvents() - 1) {
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const backsetEvent = stack.getNthFromTop(undoPtr);
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const selectionEvent = stack.getNthFromTop(undoPtr + 1);
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@ -259,9 +259,9 @@ var undoModule = (function () {
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stack.pushEvent(undoEvent);
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undoPtr += 2;
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} else { eventFunc(); }
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}
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};
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function performRedo(eventFunc) {
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const performRedo = (eventFunc) => {
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if (undoPtr >= 2) {
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const backsetEvent = stack.getNthFromTop(0);
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const selectionEvent = stack.getNthFromTop(1);
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@ -269,11 +269,9 @@ var undoModule = (function () {
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stack.popEvent();
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undoPtr -= 2;
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} else { eventFunc(); }
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}
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};
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function getAPool() {
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return undoModule.apool;
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}
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const getAPool = () => undoModule.apool;
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return {
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clearHistory,
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