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<!DOCTYPE html><html class="default"><head><meta charSet="utf-8"/><meta http-equiv="x-ua-compatible" content="IE=edge"/><title>UndoManager | GoJS API</title><meta name="description" content="Documentation for GoJS API"/><meta name="viewport" content="width=device-width, initial-scale=1"/><link rel="stylesheet" href="../../assets/css/style.css"/><link rel="stylesheet" href="../assets/style-tsd.css"/><link rel="stylesheet" href="../assets/highlight.css"/><script async src="../assets/search.js" id="search-script"></script></head><body><script>document.body.classList.add(localStorage.getItem("tsd-theme") || "os")</script><header><nav id="navTop" class="w-full z-30 top-0 text-white bg-nwoods-primary"><div class="w-full container max-w-screen-lg mx-auto flex flex-wrap sm:flex-nowrap items-center justify-between mt-0 py-2"><div class="md:pl-4"><a class="text-white hover:text-white no-underline hover:no-underline\n font-bold text-2xl lg:text-4xl rounded-lg hover:bg-nwoods-secondary" href="../../index.html"><h1 class="my-0 p-1 leading-none">GoJS</h1></a></div><button id="topnavButton" class="rounded-lg sm:hidden focus:outline-none focus:ring" aria-label="Navigation"><svg fill="currentColor" viewBox="0 0 20 20" class="w-6 h-6"><path id="topnavOpen" fill-rule="evenodd" d="M3 5a1 1 0 011-1h12a1 1 0 110 2H4a1 1 0 01-1-1zM3 10a1 1 0 011-1h12a1 1 0 110 2H4a1 1 0 01-1-1zM9 15a1 1 0 011-1h6a1 1 0 110 2h-6a1 1 0 01-1-1z" clip-rule="evenodd"></path><path id="topnavClosed" class="hidden" fill-rule="evenodd" d="M4.293 4.293a1 1 0 011.414 0L10 8.586l4.293-4.293a1 1 0 111.414 1.414L11.414 10l4.293 4.293a1 1 0 01-1.414 1.414L10 11.414l-4.293 4.293a1 1 0 01-1.414-1.414L8.586 10 4.293 5.707a1 1 0 010-1.414z" clip-rule="evenodd"></path></svg></button><div id="topnavList" class="hidden sm:block items-center w-auto mt-0 text-white p-0 z-20"><ul class="list-reset list-none font-semibold flex justify-end flex-wrap sm:flex-nowrap items-center px-0 pb-0"><li class="p-1 sm:p-0"><a class="topnav-link" href="../../learn/index.html">Learn</a></li><li class="p-1 sm:p-0"><a class="topnav-link" href="../../samples/index.html">Samples</a></li><li class="p-1 sm:p-0"><a class="topnav-link" href="../../intro/index.html">Intro</a></li><li class="p-1 sm:p-0"><a class="topnav-link" href="../../api/index.html">API</a></li><li class="p-1 sm:p-0"><a class="topnav-link" href="https://www.nwoods.com/products/register.html">Register</a></li><li class="p-1 sm:p-0"><a class="topnav-link" href="../../download.html">Download</a></li><li class="p-1 sm:p-0"><a class="topnav-link" href="https://forum.nwoods.com/c/gojs/11">Forum</a></li><li class="p-1 sm:p-0"><a class="topnav-link" href="https://www.nwoods.com/contact.html" target="_blank" rel="noopener" id="contactBtn">Contact</a></li><li class="p-1 sm:p-0"><a class="topnav-link" href="https://www.nwoods.com/sales/index.html" target="_blank" rel="noopener" id="buyBtn">Buy</a></li></ul></div></div><hr class="border-b border-gray-600 opacity-50 my-0 py-0"/></nav><div class="tsd-page-header"><div class="tsd-page-toolbar"><div class="w-full max-w-screen-xl mx-auto px-2"><div class="table-wrap"><div class="table-cell" id="tsd-search" data-base=".."><div class="field"><label for="tsd-search-field" class="tsd-widget search no-caption">Search</label><input type="text" id="tsd-search-field"/></div><ul class="results"><li class="state loading">Preparing search index...</li><li class="state failure">The search index is not available</li></ul><a href="../index.html" class="title">GoJS API</a></div><div class="table-cell" id="tsd-widgets"><div id="tsd-filter"><a href="#" class="tsd-widget options no-caption" data-toggle="options">Options</a><div class="tsd-filter-group"><div class="tsd-select" id="tsd-filter-visibility"><span class="tsd-select-label">All</span><ul class="tsd-select-list"><li data-value="public">Public</li><li data-value="protected">Public/Protected</li><li data-value="private" class="selected">All</li></ul></div> <input type="checkbox" id="tsd-filter-inherited"/><label class="tsd-widget" for="tsd-filter-inherited">Inherited</label></div></div><a href="#" class="tsd-widget menu no-caption" data-toggle="menu">Menu</a></div></div></div></div></div><div class="tsd-page-title"><div class="w-full max-w-screen-xl mx-auto px-2"><div class="top-copyright"><b>GoJS</b>® Diagramming Components<br/>version 2.3.8<br/>by <a href="https://www.nwoods.com/">Northwoods Software®</a></div><div><h1>Class UndoManager </h1></div></div></div></header><div class="tsd w-full max-w-screen-xl mx-auto pb-4"><div class="row px-2 w-full"><div class="col-8 col-content"><section class="tsd-panel tsd-hierarchy"><h3>Hierarchy</h3><ul class="tsd-hierarchy"><li><span class="target">UndoManager</span></li></ul></section><section class="tsd-panel tsd-comment"><div class="tsd-comment tsd-typography">
<p>An UndoManager observes and records model and diagram changes in transactions and
supports undo/redo operations.
You will need to set the <a href="UndoManager.html#isEnabled">isEnabled</a> property to true in order for
the UndoManager to record changes and for users to perform an undo or a redo.</p>
<div><p>Typically an operation will call <a href="UndoManager.html#startTransaction">startTransaction</a>,
make some changes to the <a href="Model.html">Model</a> and/or <a href="Diagram.html">Diagram</a>,
and then call <a href="UndoManager.html#commitTransaction">commitTransaction</a>.
Any <a href="ChangedEvent.html">ChangedEvent</a>s that occur will be recorded in a
<a href="Transaction.html">Transaction</a> object.
If for some reason you do not wish to complete the transaction
successfully, you can call <a href="UndoManager.html#rollbackTransaction">rollbackTransaction</a> instead
of <a href="UndoManager.html#commitTransaction">commitTransaction</a>.</p>
<p>For convenience the <a href="Diagram.html#commit">Diagram.commit</a> and <a href="Model.html#commit">Model.commit</a> methods
execute a function within a transaction and then perform a commit,
or else a rollback upon an error.</p>
<p>The <a href="UndoManager.html#history">history</a> property is a list of <a href="Transaction.html">Transaction</a>s.
<a href="UndoManager.html#commitTransaction">commitTransaction</a> will add the <a href="UndoManager.html#currentTransaction">currentTransaction</a>
to the <a href="UndoManager.html#history">history</a> list.
<a href="UndoManager.html#rollbackTransaction">rollbackTransaction</a> will undo the changes remembered in the
<a href="UndoManager.html#currentTransaction">currentTransaction</a> and then discard it, without changing the <a href="UndoManager.html#history">history</a>.
You can limit how many transactions are remembered in the history
by setting <a href="UndoManager.html#maxHistoryLength">maxHistoryLength</a>.</p>
<p>Transactions may be nested.
Be sure to call either <a href="UndoManager.html#commitTransaction">commitTransaction</a> or <a href="UndoManager.html#rollbackTransaction">rollbackTransaction</a>
for each call to <a href="UndoManager.html#startTransaction">startTransaction</a>.
Avoid repeated start-commit-start-commit calls as a result of a user's actions.
Instead, start, make all changes, and then commit.</p>
<p>If you want to restore the diagram to the state before the latest complete
transaction, call <a href="UndoManager.html#undo">undo</a>.
Call <a href="UndoManager.html#redo">redo</a> to change the diagram to a later state.
If after some number of undo's you start a transaction,
all of the history after the current state is discarded,
and a new transaction may be recorded.
You cannot undo or redo during a transaction.</p>
<p>Initially each <a href="Model.html">Model</a> has its own UndoManager.
UndoManagers may be shared by multiple Models by replacing
the standard <a href="Model.html#undoManager">Model.undoManager</a> created by the model constructor.</p>
<p>There are several informational properties:</p>
<ul>
<li><a href="UndoManager.html#isInTransaction">isInTransaction</a> is true when a top-level transaction has been started that has not yet been committed or rolled-back.</li>
<li><a href="UndoManager.html#currentTransaction">currentTransaction</a> holds the flattened list of all <a href="ChangedEvent.html">ChangedEvent</a>s
that have happened within the current transaction.</li>
<li><a href="UndoManager.html#transactionLevel">transactionLevel</a> indicates the current depth of nesting.</li>
<li><a href="UndoManager.html#nestedTransactionNames">nestedTransactionNames</a> holds the stack of transaction names supplied to
<a href="UndoManager.html#startTransaction">startTransaction</a> calls.</li>
<li><a href="UndoManager.html#history">history</a> holds only complete top-level transactions.</li>
<li><a href="UndoManager.html#isUndoingRedoing">isUndoingRedoing</a> is true during a call to <a href="UndoManager.html#undo">undo</a> or <a href="UndoManager.html#redo">redo</a>.</li>
<li><a href="UndoManager.html#historyIndex">historyIndex</a> indicates which <a href="Transaction.html">Transaction</a> in the <a href="UndoManager.html#history">history</a> is the next to be "undone";
this is decremented by each undo and incremented by each redo.</li>
<li><a href="UndoManager.html#transactionToUndo">transactionToUndo</a> and <a href="UndoManager.html#transactionToRedo">transactionToRedo</a> indicate which <a href="Transaction.html">Transaction</a> may be undone or redone next, if any.</li>
<li><a href="UndoManager.html#models">models</a> returns an iterator over all of the <a href="Model.html">Model</a>s that this UndoManager is handling.</li>
</ul>
<p>A transaction may not be ongoing when replacing a <a href="Diagram.html#model">Diagram.model</a>,
because it would not make sense to be replacing the UndoManager (the <a href="Model.html#undoManager">Model.undoManager</a>)
while changes are being recorded.</p>
<p>Replacing a <a href="Diagram.html#model">Diagram.model</a> copies certain properties from the old UndoManager to the new one,
including <a href="UndoManager.html#isEnabled">isEnabled</a> and <a href="UndoManager.html#maxHistoryLength">maxHistoryLength</a>.</p>
</div></div></section><section class="tsd-panel-group tsd-index-group"><h2>Index</h2><section class="tsd-panel tsd-index-panel"><div class="tsd-index-content"><section class="tsd-index-section "><h3>Constructors</h3><ul class="tsd-index-list"><li class="tsd-kind-constructor tsd-parent-kind-class"><a href="UndoManager.html#constructor" class="tsd-kind-icon">constructor</a></li></ul></section><section class="tsd-index-section "><h3>Properties</h3><ul class="tsd-index-list"><li class="tsd-kind-get-signature tsd-parent-kind-class"><a href="UndoManager.html#currentTransaction" class="tsd-kind-icon">current<wbr/>Transaction</a></li><li class="tsd-kind-get-signature tsd-parent-kind-class"><a href="UndoManager.html#history" class="tsd-kind-icon">history</a></li><li class="tsd-kind-get-signature tsd-parent-kind-class"><a href="UndoManager.html#historyIndex" class="tsd-kind-icon">history<wbr/>Index</a></li><li class="tsd-kind-accessor tsd-parent-kind-class"><a href="UndoManager.html#isEnabled" class="tsd-kind-icon">is<wbr/>Enabled</a></li><li class="tsd-kind-get-signature tsd-parent-kind-class"><a href="UndoManager.html#isInTransaction" class="tsd-kind-icon">is<wbr/>In<wbr/>Transaction</a></li><li class="tsd-kind-get-signature tsd-parent-kind-class"><a href="UndoManager.html#isUndoingRedoing" class="tsd-kind-icon">is<wbr/>Undoing<wbr/>Redoing</a></li><li class="tsd-kind-accessor tsd-parent-kind-class"><a href="UndoManager.html#maxHistoryLength" class="tsd-kind-icon">max<wbr/>History<wbr/>Length</a></li><li class="tsd-kind-get-signature tsd-parent-kind-class"><a href="UndoManager.html#models" class="tsd-kind-icon">models</a></li><li class="tsd-kind-get-signature tsd-parent-kind-class"><a href="UndoManager.html#nestedTransactionNames" class="tsd-kind-icon">nested<wbr/>Transaction<wbr/>Names</a></li><li class="tsd-kind-get-signature tsd-parent-kind-class"><a href="UndoManager.html#transactionLevel" class="tsd-kind-icon">transaction<wbr/>Level</a></li><li class="tsd-kind-get-signature tsd-parent-kind-class"><a href="UndoManager.html#transactionToRedo" class="tsd-kind-icon">transaction<wbr/>To<wbr/>Redo</a></li><li class="tsd-kind-get-signature tsd-parent-kind-class"><a href="UndoManager.html#transactionToUndo" class="tsd-kind-icon">transaction<wbr/>To<wbr/>Undo</a></li></ul></section><section class="tsd-index-section "><h3>Methods</h3><ul class="tsd-index-list"><li class="tsd-kind-method tsd-parent-kind-class"><a href="UndoManager.html#addModel" class="tsd-kind-icon">add<wbr/>Model</a></li><li class="tsd-kind-method tsd-parent-kind-class"><a href="UndoManager.html#canRedo" class="tsd-kind-icon">can<wbr/>Redo</a></li><li class="tsd-kind-method tsd-parent-kind-class"><a href="UndoManager.html#canUndo" class="tsd-kind-icon">can<wbr/>Undo</a></li><li class="tsd-kind-method tsd-parent-kind-class"><a href="UndoManager.html#clear" class="tsd-kind-icon">clear</a></li><li class="tsd-kind-method tsd-parent-kind-class"><a href="UndoManager.html#commitTransaction" class="tsd-kind-icon">commit<wbr/>Transaction</a></li><li class="tsd-kind-method tsd-parent-kind-class"><a href="UndoManager.html#handleChanged" class="tsd-kind-icon">handle<wbr/>Changed</a></li><li class="tsd-kind-method tsd-parent-kind-class"><a href="UndoManager.html#redo" class="tsd-kind-icon">redo</a></li><li class="tsd-kind-method tsd-parent-kind-class"><a href="UndoManager.html#removeModel" class="tsd-kind-icon">remove<wbr/>Model</a></li><li class="tsd-kind-method tsd-parent-kind-class"><a href="UndoManager.html#rollbackTransaction" class="tsd-kind-icon">rollback<wbr/>Transaction</a></li><li class="tsd-kind-method tsd-parent-kind-class"><a href="UndoManager.html#skipsEvent" class="tsd-kind-icon">skips<wbr/>Event</a></li><li class="tsd-kind-method tsd-parent-kind-class"><a href="UndoManager.html#startTransaction" class="tsd-kind-icon">start<wbr/>Transaction</a></li><li class="tsd-kind-method tsd-parent-kind-class"><a href="UndoManager.html#undo" class="tsd-kind-icon">undo</a></li></ul></section></div></section></section><section class="tsd-panel-group tsd-member-group "><h2>Constructors</h2><section class="tsd-panel tsd-member tsd-kind-constructor tsd-parent-kind-class"><a id="constructor" class="tsd-anchor"></a><h3 class="tsd-anchor-link"> constructor<a href="#constructor" aria-label="Permalink" class="tsd-anchor-icon"><svg xmlns="http://www.w3.org/2000/svg" class="icon icon-tabler icon-tabler-link" viewBox="0 0 24 24" stroke-width="2" stroke="currentColor" fill="none" stroke-linecap="round" stroke-linejoin="round"><path stroke="none" d="M0 0h24v24H0z" fill="none"></path><path d="M10 14a3.5 3.5 0 0 0 5 0l4 -4a3.5 3.5 0 0 0 -5 -5l-.5 .5"></path><path d="M14 10a3.5 3.5 0 0 0 -5 0l-4 4a3.5 3.5 0 0 0 5 5l.5 -.5"></path></svg></a></h3><ul class="tsd-signatures tsd-kind-constructor tsd-parent-kind-class"><li class="tsd-signature tsd-kind-icon">new <wbr/>Undo<wbr/>Manager<span class="tsd-signature-symbol">(</span><span class="tsd-signature-symbol">)</span><span class="tsd-signature-symbol">: </span><a href="UndoManager.html" class="tsd-signature-type" data-tsd-kind="Class">UndoManager</a></li></ul><ul class="tsd-descriptions"><li class="tsd-description"><div class="tsd-comment tsd-typography">
<p>The constructor produces an empty UndoManager
with no transaction history.</p>
</div><h4 class="tsd-returns-title">Returns <a href="UndoManager.html" class="tsd-signature-type" data-tsd-kind="Class">UndoManager</a></h4></li></ul></section></section><section class="tsd-panel-group tsd-member-group "><h2>Properties</h2><section class="tsd-panel tsd-member tsd-kind-get-signature tsd-parent-kind-class"><a id="currentTransaction" class="tsd-anchor"></a><h3 class="tsd-anchor-link"><span class="tsd-flag ts-flagReadOnly">Read-only</span> current<wbr/>Transaction<span class="tsd-signature-symbol">: </span><a href="Transaction.html" class="tsd-signature-type" data-tsd-kind="Class">Transaction</a><a href="#currentTransaction" aria-label="Permalink" class="tsd-anchor-icon"><svg xmlns="http://www.w3.org/2000/svg" class="icon icon-tabler icon-tabler-link" viewBox="0 0 24 24" stroke-width="2" stroke="currentColor" fill="none" stroke-linecap="round" stroke-linejoin="round"><path stroke="none" d="M0 0h24v24H0z" fill="none"></path><path d="M10 14a3.5 3.5 0 0 0 5 0l4 -4a3.5 3.5 0 0 0 -5 -5l-.5 .5"></path><path d="M14 10a3.5 3.5 0 0 0 -5 0l-4 4a3.5 3.5 0 0 0 5 5l.5 -.5"></path></svg></a></h3><ul class="tsd-descriptions"><li class="tsd-description"><div class="tsd-comment tsd-typography">
<p>This read-only property returns the current <a href="Transaction.html">Transaction</a> for recording additional model change events.
This is initialized and augmented by <a href="UndoManager.html#handleChanged">handleChanged</a>
before it is added to <a href="UndoManager.html#history">history</a> by a top-level call
to <a href="UndoManager.html#commitTransaction">commitTransaction</a>.
The value will be null between transactions.</p>
</div></li></ul></section><section class="tsd-panel tsd-member tsd-kind-get-signature tsd-parent-kind-class"><a id="history" class="tsd-anchor"></a><h3 class="tsd-anchor-link"><span class="tsd-flag ts-flagReadOnly">Read-only</span> history<span class="tsd-signature-symbol">: </span><a href="List.html" class="tsd-signature-type" data-tsd-kind="Class">List</a><span class="tsd-signature-symbol"><</span><a href="Transaction.html" class="tsd-signature-type" data-tsd-kind="Class">Transaction</a><span class="tsd-signature-symbol">></span><a href="#history" aria-label="Permalink" class="tsd-anchor-icon"><svg xmlns="http://www.w3.org/2000/svg" class="icon icon-tabler icon-tabler-link" viewBox="0 0 24 24" stroke-width="2" stroke="currentColor" fill="none" stroke-linecap="round" stroke-linejoin="round"><path stroke="none" d="M0 0h24v24H0z" fill="none"></path><path d="M10 14a3.5 3.5 0 0 0 5 0l4 -4a3.5 3.5 0 0 0 -5 -5l-.5 .5"></path><path d="M14 10a3.5 3.5 0 0 0 -5 0l-4 4a3.5 3.5 0 0 0 5 5l.5 -.5"></path></svg></a></h3><ul class="tsd-descriptions"><li class="tsd-description"><div class="tsd-comment tsd-typography">
<p>This read-only property returns the whole history, a list of all of the <a href="Transaction.html">Transaction</a>s,
each representing a transaction with some number of <a href="ChangedEvent.html">ChangedEvent</a>s.</p>
<div><p>You should not modify this List.</p>
</div></div></li></ul></section><section class="tsd-panel tsd-member tsd-kind-get-signature tsd-parent-kind-class"><a id="historyIndex" class="tsd-anchor"></a><h3 class="tsd-anchor-link"><span class="tsd-flag ts-flagReadOnly">Read-only</span> history<wbr/>Index<span class="tsd-signature-symbol">: </span><span class="tsd-signature-type">number</span><a href="#historyIndex" aria-label="Permalink" class="tsd-anchor-icon"><svg xmlns="http://www.w3.org/2000/svg" class="icon icon-tabler icon-tabler-link" viewBox="0 0 24 24" stroke-width="2" stroke="currentColor" fill="none" stroke-linecap="round" stroke-linejoin="round"><path stroke="none" d="M0 0h24v24H0z" fill="none"></path><path d="M10 14a3.5 3.5 0 0 0 5 0l4 -4a3.5 3.5 0 0 0 -5 -5l-.5 .5"></path><path d="M14 10a3.5 3.5 0 0 0 -5 0l-4 4a3.5 3.5 0 0 0 5 5l.5 -.5"></path></svg></a></h3><ul class="tsd-descriptions"><li class="tsd-description"><div class="tsd-comment tsd-typography">
<p>This read-only property returns the index into <a href="UndoManager.html#history">history</a> for the current undoable <a href="Transaction.html">Transaction</a>.
The value is -1 if there is no undoable <a href="Transaction.html">Transaction</a> to be undone.</p>
</div></li></ul></section><section class="tsd-panel tsd-member tsd-kind-accessor tsd-parent-kind-class"><a id="isEnabled" class="tsd-anchor"></a><h3 class="tsd-anchor-link"> is<wbr/>Enabled<span class="tsd-signature-symbol">: </span><span class="tsd-signature-type">boolean</span><a href="#isEnabled" aria-label="Permalink" class="tsd-anchor-icon"><svg xmlns="http://www.w3.org/2000/svg" class="icon icon-tabler icon-tabler-link" viewBox="0 0 24 24" stroke-width="2" stroke="currentColor" fill="none" stroke-linecap="round" stroke-linejoin="round"><path stroke="none" d="M0 0h24v24H0z" fill="none"></path><path d="M10 14a3.5 3.5 0 0 0 5 0l4 -4a3.5 3.5 0 0 0 -5 -5l-.5 .5"></path><path d="M14 10a3.5 3.5 0 0 0 -5 0l-4 4a3.5 3.5 0 0 0 5 5l.5 -.5"></path></svg></a></h3><ul class="tsd-descriptions"><li class="tsd-description"><div class="tsd-comment tsd-typography">
<p>Gets or sets whether this UndoManager records any changes.
The default value is false -- you need to set this to true if
you want the user to be able to undo or redo.</p>
<div><p>You can temporarily turn off recording by setting <a href="Diagram.html#skipsUndoManager">Diagram.skipsUndoManager</a>
and <a href="Model.html#skipsUndoManager">Model.skipsUndoManager</a> to true.</p>
</div></div></li></ul></section><section class="tsd-panel tsd-member tsd-kind-get-signature tsd-parent-kind-class"><a id="isInTransaction" class="tsd-anchor"></a><h3 class="tsd-anchor-link"><span class="tsd-flag ts-flagReadOnly">Read-only</span> is<wbr/>In<wbr/>Transaction<span class="tsd-signature-symbol">: </span><span class="tsd-signature-type">boolean</span><a href="#isInTransaction" aria-label="Permalink" class="tsd-anchor-icon"><svg xmlns="http://www.w3.org/2000/svg" class="icon icon-tabler icon-tabler-link" viewBox="0 0 24 24" stroke-width="2" stroke="currentColor" fill="none" stroke-linecap="round" stroke-linejoin="round"><path stroke="none" d="M0 0h24v24H0z" fill="none"></path><path d="M10 14a3.5 3.5 0 0 0 5 0l4 -4a3.5 3.5 0 0 0 -5 -5l-.5 .5"></path><path d="M14 10a3.5 3.5 0 0 0 -5 0l-4 4a3.5 3.5 0 0 0 5 5l.5 -.5"></path></svg></a></h3><ul class="tsd-descriptions"><li class="tsd-description"><div class="tsd-comment tsd-typography">
<p>This read-only property is true after the first call to <a href="UndoManager.html#startTransaction">startTransaction</a>
and before a corresponding call to <a href="UndoManager.html#commitTransaction">commitTransaction</a> or <a href="UndoManager.html#rollbackTransaction">rollbackTransaction</a>.</p>
<div><p>During a transaction <a href="UndoManager.html#canUndo">canUndo</a> and <a href="UndoManager.html#canRedo">canRedo</a> will be false.
<a href="UndoManager.html#currentTransaction">currentTransaction</a> may be non-null if any <a href="ChangedEvent.html">ChangedEvent</a>s were recorded.</p>
</div></div></li></ul></section><section class="tsd-panel tsd-member tsd-kind-get-signature tsd-parent-kind-class"><a id="isUndoingRedoing" class="tsd-anchor"></a><h3 class="tsd-anchor-link"><span class="tsd-flag ts-flagReadOnly">Read-only</span> is<wbr/>Undoing<wbr/>Redoing<span class="tsd-signature-symbol">: </span><span class="tsd-signature-type">boolean</span><a href="#isUndoingRedoing" aria-label="Permalink" class="tsd-anchor-icon"><svg xmlns="http://www.w3.org/2000/svg" class="icon icon-tabler icon-tabler-link" viewBox="0 0 24 24" stroke-width="2" stroke="currentColor" fill="none" stroke-linecap="round" stroke-linejoin="round"><path stroke="none" d="M0 0h24v24H0z" fill="none"></path><path d="M10 14a3.5 3.5 0 0 0 5 0l4 -4a3.5 3.5 0 0 0 -5 -5l-.5 .5"></path><path d="M14 10a3.5 3.5 0 0 0 -5 0l-4 4a3.5 3.5 0 0 0 5 5l.5 -.5"></path></svg></a></h3><ul class="tsd-descriptions"><li class="tsd-description"><div class="tsd-comment tsd-typography">
<p>This read-only property is true during a call to <a href="UndoManager.html#undo">undo</a> or <a href="UndoManager.html#redo">redo</a>.</p>
</div></li></ul></section><section class="tsd-panel tsd-member tsd-kind-accessor tsd-parent-kind-class"><a id="maxHistoryLength" class="tsd-anchor"></a><h3 class="tsd-anchor-link"> max<wbr/>History<wbr/>Length<span class="tsd-signature-symbol">: </span><span class="tsd-signature-type">number</span><a href="#maxHistoryLength" aria-label="Permalink" class="tsd-anchor-icon"><svg xmlns="http://www.w3.org/2000/svg" class="icon icon-tabler icon-tabler-link" viewBox="0 0 24 24" stroke-width="2" stroke="currentColor" fill="none" stroke-linecap="round" stroke-linejoin="round"><path stroke="none" d="M0 0h24v24H0z" fill="none"></path><path d="M10 14a3.5 3.5 0 0 0 5 0l4 -4a3.5 3.5 0 0 0 -5 -5l-.5 .5"></path><path d="M14 10a3.5 3.5 0 0 0 -5 0l-4 4a3.5 3.5 0 0 0 5 5l.5 -.5"></path></svg></a></h3><ul class="tsd-descriptions"><li class="tsd-description"><div class="tsd-comment tsd-typography">
<p>Gets or sets the maximum number of transactions that this undo manager will remember.
When a transaction is committed and the number exceeds this value,
the UndoManager will discard the oldest transaction(s) in order to meet this limit.
The initial value is 999.
Any new value must be an integer.
A negative value is treated as if there were no limit.
A zero value will not remember any Transactions in the <a href="UndoManager.html#history">history</a>,
but will allow commits and rollbacks to occur normally,
including raising "Transaction" type <a href="ChangedEvent.html">ChangedEvent</a>s.</p>
<div><p>This property is useful in helping limit the memory consumption of typical applications.
But this does not limit the number of <a href="ChangedEvent.html">ChangedEvent</a>s that are recorded,
because there may be an unlimited number of those within each <a href="Transaction.html">Transaction</a>.
Decreasing this value will not necessarily remove any existing <a href="Transaction.html">Transaction</a>s
if there currently exist more in <a href="UndoManager.html#history">history</a> than the new value permits.</p>
</div></div></li></ul></section><section class="tsd-panel tsd-member tsd-kind-get-signature tsd-parent-kind-class"><a id="models" class="tsd-anchor"></a><h3 class="tsd-anchor-link"><span class="tsd-flag ts-flagReadOnly">Read-only</span> models<span class="tsd-signature-symbol">: </span><a href="Iterator.html" class="tsd-signature-type" data-tsd-kind="Interface">Iterator</a><span class="tsd-signature-symbol"><</span><a href="Model.html" class="tsd-signature-type" data-tsd-kind="Class">Model</a><span class="tsd-signature-symbol">></span><a href="#models" aria-label="Permalink" class="tsd-anchor-icon"><svg xmlns="http://www.w3.org/2000/svg" class="icon icon-tabler icon-tabler-link" viewBox="0 0 24 24" stroke-width="2" stroke="currentColor" fill="none" stroke-linecap="round" stroke-linejoin="round"><path stroke="none" d="M0 0h24v24H0z" fill="none"></path><path d="M10 14a3.5 3.5 0 0 0 5 0l4 -4a3.5 3.5 0 0 0 -5 -5l-.5 .5"></path><path d="M14 10a3.5 3.5 0 0 0 -5 0l-4 4a3.5 3.5 0 0 0 5 5l.5 -.5"></path></svg></a></h3><ul class="tsd-descriptions"><li class="tsd-description"><div class="tsd-comment tsd-typography">
<p>This read-only property returns an iterator for all of the <a href="Model.html">Model</a>s that this UndoManager is handling.</p>
<dl class="tsd-comment-tags"><dt class="">see</dt><dd><p><a href="UndoManager.html#addModel">addModel</a>, <a href="UndoManager.html#removeModel">removeModel</a></p>
</dd></dl></div></li></ul></section><section class="tsd-panel tsd-member tsd-kind-get-signature tsd-parent-kind-class"><a id="nestedTransactionNames" class="tsd-anchor"></a><h3 class="tsd-anchor-link"><span class="tsd-flag ts-flagReadOnly">Read-only</span> nested<wbr/>Transaction<wbr/>Names<span class="tsd-signature-symbol">: </span><a href="List.html" class="tsd-signature-type" data-tsd-kind="Class">List</a><span class="tsd-signature-symbol"><</span><span class="tsd-signature-type">string</span><span class="tsd-signature-symbol">></span><a href="#nestedTransactionNames" aria-label="Permalink" class="tsd-anchor-icon"><svg xmlns="http://www.w3.org/2000/svg" class="icon icon-tabler icon-tabler-link" viewBox="0 0 24 24" stroke-width="2" stroke="currentColor" fill="none" stroke-linecap="round" stroke-linejoin="round"><path stroke="none" d="M0 0h24v24H0z" fill="none"></path><path d="M10 14a3.5 3.5 0 0 0 5 0l4 -4a3.5 3.5 0 0 0 -5 -5l-.5 .5"></path><path d="M14 10a3.5 3.5 0 0 0 -5 0l-4 4a3.5 3.5 0 0 0 5 5l.5 -.5"></path></svg></a></h3><ul class="tsd-descriptions"><li class="tsd-description"><div class="tsd-comment tsd-typography">
<p>This read-only property returns a stack of ongoing transaction names.
The outermost transaction name will be the first item in the list.
The last one will be the name of the most recent (nested) call
to <a href="UndoManager.html#startTransaction">startTransaction</a>.</p>
<div><p>You should not modify this List.</p>
</div></div></li></ul></section><section class="tsd-panel tsd-member tsd-kind-get-signature tsd-parent-kind-class"><a id="transactionLevel" class="tsd-anchor"></a><h3 class="tsd-anchor-link"><span class="tsd-flag ts-flagReadOnly">Read-only</span> transaction<wbr/>Level<span class="tsd-signature-symbol">: </span><span class="tsd-signature-type">number</span><a href="#transactionLevel" aria-label="Permalink" class="tsd-anchor-icon"><svg xmlns="http://www.w3.org/2000/svg" class="icon icon-tabler icon-tabler-link" viewBox="0 0 24 24" stroke-width="2" stroke="currentColor" fill="none" stroke-linecap="round" stroke-linejoin="round"><path stroke="none" d="M0 0h24v24H0z" fill="none"></path><path d="M10 14a3.5 3.5 0 0 0 5 0l4 -4a3.5 3.5 0 0 0 -5 -5l-.5 .5"></path><path d="M14 10a3.5 3.5 0 0 0 -5 0l-4 4a3.5 3.5 0 0 0 5 5l.5 -.5"></path></svg></a></h3><ul class="tsd-descriptions"><li class="tsd-description"><div class="tsd-comment tsd-typography">
<p>This read-only property returns the current transaction level.
The value is zero when there is no ongoing transaction.
The initial value is zero.
<a href="UndoManager.html#startTransaction">startTransaction</a> will increment this value;
<a href="UndoManager.html#commitTransaction">commitTransaction</a> or <a href="UndoManager.html#rollbackTransaction">rollbackTransaction</a> will decrement it.
When this value is greater than zero, <a href="UndoManager.html#canUndo">canUndo</a>
and <a href="UndoManager.html#canRedo">canRedo</a> will be false, because
additional logically related model change events may occur.</p>
</div></li></ul></section><section class="tsd-panel tsd-member tsd-kind-get-signature tsd-parent-kind-class"><a id="transactionToRedo" class="tsd-anchor"></a><h3 class="tsd-anchor-link"><span class="tsd-flag ts-flagReadOnly">Read-only</span> transaction<wbr/>To<wbr/>Redo<span class="tsd-signature-symbol">: </span><a href="Transaction.html" class="tsd-signature-type" data-tsd-kind="Class">Transaction</a><a href="#transactionToRedo" aria-label="Permalink" class="tsd-anchor-icon"><svg xmlns="http://www.w3.org/2000/svg" class="icon icon-tabler icon-tabler-link" viewBox="0 0 24 24" stroke-width="2" stroke="currentColor" fill="none" stroke-linecap="round" stroke-linejoin="round"><path stroke="none" d="M0 0h24v24H0z" fill="none"></path><path d="M10 14a3.5 3.5 0 0 0 5 0l4 -4a3.5 3.5 0 0 0 -5 -5l-.5 .5"></path><path d="M14 10a3.5 3.5 0 0 0 -5 0l-4 4a3.5 3.5 0 0 0 5 5l.5 -.5"></path></svg></a></h3><ul class="tsd-descriptions"><li class="tsd-description"><div class="tsd-comment tsd-typography">
<p>This read-only property returns the <a href="Transaction.html">Transaction</a> in the <a href="UndoManager.html#history">history</a> to be redone next.
The value may be null if the UndoManager is not ready to perform a redo.</p>
<dl class="tsd-comment-tags"><dt class="">see</dt><dd><p><a href="UndoManager.html#transactionToUndo">transactionToUndo</a></p>
</dd></dl></div></li></ul></section><section class="tsd-panel tsd-member tsd-kind-get-signature tsd-parent-kind-class"><a id="transactionToUndo" class="tsd-anchor"></a><h3 class="tsd-anchor-link"><span class="tsd-flag ts-flagReadOnly">Read-only</span> transaction<wbr/>To<wbr/>Undo<span class="tsd-signature-symbol">: </span><a href="Transaction.html" class="tsd-signature-type" data-tsd-kind="Class">Transaction</a><a href="#transactionToUndo" aria-label="Permalink" class="tsd-anchor-icon"><svg xmlns="http://www.w3.org/2000/svg" class="icon icon-tabler icon-tabler-link" viewBox="0 0 24 24" stroke-width="2" stroke="currentColor" fill="none" stroke-linecap="round" stroke-linejoin="round"><path stroke="none" d="M0 0h24v24H0z" fill="none"></path><path d="M10 14a3.5 3.5 0 0 0 5 0l4 -4a3.5 3.5 0 0 0 -5 -5l-.5 .5"></path><path d="M14 10a3.5 3.5 0 0 0 -5 0l-4 4a3.5 3.5 0 0 0 5 5l.5 -.5"></path></svg></a></h3><ul class="tsd-descriptions"><li class="tsd-description"><div class="tsd-comment tsd-typography">
<p>This read-only property returns the <a href="Transaction.html">Transaction</a> in the <a href="UndoManager.html#history">history</a> to be undone next.
The value may be null if the UndoManager is not ready to perform an undo.</p>
<dl class="tsd-comment-tags"><dt class="">see</dt><dd><p><a href="UndoManager.html#transactionToRedo">transactionToRedo</a></p>
</dd></dl></div></li></ul></section></section><section class="tsd-panel-group tsd-member-group "><h2>Methods</h2><section class="tsd-panel tsd-member tsd-kind-method tsd-parent-kind-class"><a id="addModel" class="tsd-anchor"></a><h3 class="tsd-anchor-link"> add<wbr/>Model<a href="#addModel" aria-label="Permalink" class="tsd-anchor-icon"><svg xmlns="http://www.w3.org/2000/svg" class="icon icon-tabler icon-tabler-link" viewBox="0 0 24 24" stroke-width="2" stroke="currentColor" fill="none" stroke-linecap="round" stroke-linejoin="round"><path stroke="none" d="M0 0h24v24H0z" fill="none"></path><path d="M10 14a3.5 3.5 0 0 0 5 0l4 -4a3.5 3.5 0 0 0 -5 -5l-.5 .5"></path><path d="M14 10a3.5 3.5 0 0 0 -5 0l-4 4a3.5 3.5 0 0 0 5 5l.5 -.5"></path></svg></a></h3><ul class="tsd-signatures tsd-kind-method tsd-parent-kind-class"><li class="tsd-signature tsd-kind-icon">add<wbr/>Model<span class="tsd-signature-symbol">(</span>model<span class="tsd-signature-symbol">: </span><a href="Model.html" class="tsd-signature-type" data-tsd-kind="Class">Model</a><span class="tsd-signature-symbol">)</span><span class="tsd-signature-symbol">: </span><span class="tsd-signature-type">void</span></li></ul><ul class="tsd-descriptions"><li class="tsd-description"><div class="tsd-comment tsd-typography">
<p>Make sure this UndoManager knows about a <a href="Model.html">Model</a> for which
it may receive <a href="ChangedEvent.html">ChangedEvent</a>s when the given <a href="Model.html">Model</a> is changed.
The model will also receive notifications about transactions and undo or redo operations.</p>
<div><p>You should not call this method during a transaction.</p>
</div><dl class="tsd-comment-tags"><dt class="">see</dt><dd><p><a href="UndoManager.html#models">models</a>, <a href="UndoManager.html#removeModel">removeModel</a></p>
</dd></dl></div><h4 class="tsd-parameters-title">Parameters</h4><ul class="tsd-parameters"><li><h5>model: <a href="Model.html" class="tsd-signature-type" data-tsd-kind="Class">Model</a></h5><div class="tsd-comment tsd-typography">
<p>A <a href="Model.html">Model</a> that this UndoManager is managing.</p>
</div></li></ul><h4 class="tsd-returns-title">Returns <span class="tsd-signature-type">void</span></h4></li></ul></section><section class="tsd-panel tsd-member tsd-kind-method tsd-parent-kind-class"><a id="canRedo" class="tsd-anchor"></a><h3 class="tsd-anchor-link"> can<wbr/>Redo<a href="#canRedo" aria-label="Permalink" class="tsd-anchor-icon"><svg xmlns="http://www.w3.org/2000/svg" class="icon icon-tabler icon-tabler-link" viewBox="0 0 24 24" stroke-width="2" stroke="currentColor" fill="none" stroke-linecap="round" stroke-linejoin="round"><path stroke="none" d="M0 0h24v24H0z" fill="none"></path><path d="M10 14a3.5 3.5 0 0 0 5 0l4 -4a3.5 3.5 0 0 0 -5 -5l-.5 .5"></path><path d="M14 10a3.5 3.5 0 0 0 -5 0l-4 4a3.5 3.5 0 0 0 5 5l.5 -.5"></path></svg></a></h3><ul class="tsd-signatures tsd-kind-method tsd-parent-kind-class"><li class="tsd-signature tsd-kind-icon">can<wbr/>Redo<span class="tsd-signature-symbol">(</span><span class="tsd-signature-symbol">)</span><span class="tsd-signature-symbol">: </span><span class="tsd-signature-type">boolean</span></li></ul><ul class="tsd-descriptions"><li class="tsd-description"><div class="tsd-comment tsd-typography">
<p>This predicate returns true if you can call <a href="UndoManager.html#redo">redo</a>.
This will return false if <a href="UndoManager.html#isEnabled">isEnabled</a> is false (as it is by default),
if any transaction is ongoing, or
if there is no <a href="UndoManager.html#transactionToRedo">transactionToRedo</a> that can be redone.</p>
</div><h4 class="tsd-returns-title">Returns <span class="tsd-signature-type">boolean</span></h4><div><p>true if ready for <a href="UndoManager.html#redo">redo</a> to be called.</p>
</div></li></ul></section><section class="tsd-panel tsd-member tsd-kind-method tsd-parent-kind-class"><a id="canUndo" class="tsd-anchor"></a><h3 class="tsd-anchor-link"> can<wbr/>Undo<a href="#canUndo" aria-label="Permalink" class="tsd-anchor-icon"><svg xmlns="http://www.w3.org/2000/svg" class="icon icon-tabler icon-tabler-link" viewBox="0 0 24 24" stroke-width="2" stroke="currentColor" fill="none" stroke-linecap="round" stroke-linejoin="round"><path stroke="none" d="M0 0h24v24H0z" fill="none"></path><path d="M10 14a3.5 3.5 0 0 0 5 0l4 -4a3.5 3.5 0 0 0 -5 -5l-.5 .5"></path><path d="M14 10a3.5 3.5 0 0 0 -5 0l-4 4a3.5 3.5 0 0 0 5 5l.5 -.5"></path></svg></a></h3><ul class="tsd-signatures tsd-kind-method tsd-parent-kind-class"><li class="tsd-signature tsd-kind-icon">can<wbr/>Undo<span class="tsd-signature-symbol">(</span><span class="tsd-signature-symbol">)</span><span class="tsd-signature-symbol">: </span><span class="tsd-signature-type">boolean</span></li></ul><ul class="tsd-descriptions"><li class="tsd-description"><div class="tsd-comment tsd-typography">
<p>This predicate returns true if you can call <a href="UndoManager.html#undo">undo</a>.
This will return false if <a href="UndoManager.html#isEnabled">isEnabled</a> is false (as it is by default),
if any transaction is ongoing, or
if there is no <a href="UndoManager.html#transactionToUndo">transactionToUndo</a> that can be undone.</p>
</div><h4 class="tsd-returns-title">Returns <span class="tsd-signature-type">boolean</span></h4><div><p>true if ready for <a href="UndoManager.html#undo">undo</a> to be called.</p>
</div></li></ul></section><section class="tsd-panel tsd-member tsd-kind-method tsd-parent-kind-class"><a id="clear" class="tsd-anchor"></a><h3 class="tsd-anchor-link"> clear<a href="#clear" aria-label="Permalink" class="tsd-anchor-icon"><svg xmlns="http://www.w3.org/2000/svg" class="icon icon-tabler icon-tabler-link" viewBox="0 0 24 24" stroke-width="2" stroke="currentColor" fill="none" stroke-linecap="round" stroke-linejoin="round"><path stroke="none" d="M0 0h24v24H0z" fill="none"></path><path d="M10 14a3.5 3.5 0 0 0 5 0l4 -4a3.5 3.5 0 0 0 -5 -5l-.5 .5"></path><path d="M14 10a3.5 3.5 0 0 0 -5 0l-4 4a3.5 3.5 0 0 0 5 5l.5 -.5"></path></svg></a></h3><ul class="tsd-signatures tsd-kind-method tsd-parent-kind-class"><li class="tsd-signature tsd-kind-icon">clear<span class="tsd-signature-symbol">(</span><span class="tsd-signature-symbol">)</span><span class="tsd-signature-symbol">: </span><span class="tsd-signature-type">void</span></li></ul><ul class="tsd-descriptions"><li class="tsd-description"><div class="tsd-comment tsd-typography">
<p>Clear all of the <a href="Transaction.html">Transaction</a>s and clear all other state,
including any ongoing transaction without rolling back.
However, this maintains its references to its <a href="Model.html">Model</a>s.</p>
<div><p>You should not call this method during a transaction.</p>
</div></div><h4 class="tsd-returns-title">Returns <span class="tsd-signature-type">void</span></h4></li></ul></section><section class="tsd-panel tsd-member tsd-kind-method tsd-parent-kind-class"><a id="commitTransaction" class="tsd-anchor"></a><h3 class="tsd-anchor-link"> commit<wbr/>Transaction<a href="#commitTransaction" aria-label="Permalink" class="tsd-anchor-icon"><svg xmlns="http://www.w3.org/2000/svg" class="icon icon-tabler icon-tabler-link" viewBox="0 0 24 24" stroke-width="2" stroke="currentColor" fill="none" stroke-linecap="round" stroke-linejoin="round"><path stroke="none" d="M0 0h24v24H0z" fill="none"></path><path d="M10 14a3.5 3.5 0 0 0 5 0l4 -4a3.5 3.5 0 0 0 -5 -5l-.5 .5"></path><path d="M14 10a3.5 3.5 0 0 0 -5 0l-4 4a3.5 3.5 0 0 0 5 5l.5 -.5"></path></svg></a></h3><ul class="tsd-signatures tsd-kind-method tsd-parent-kind-class"><li class="tsd-signature tsd-kind-icon">commit<wbr/>Transaction<span class="tsd-signature-symbol">(</span>tname<span class="tsd-signature-symbol">?: </span><span class="tsd-signature-type">string</span><span class="tsd-signature-symbol">)</span><span class="tsd-signature-symbol">: </span><span class="tsd-signature-type">boolean</span></li></ul><ul class="tsd-descriptions"><li class="tsd-description"><div class="tsd-comment tsd-typography">
<p>Commit the current transaction started by a call to <a href="UndoManager.html#startTransaction">startTransaction</a>.</p>
<div><p>For convenience, this method is called by <a href="Model.html#commitTransaction">Model.commitTransaction</a> and <a href="Diagram.html#commitTransaction">Diagram.commitTransaction</a>.</p>
<p>If this call stops a top-level transaction,
we mark the <a href="UndoManager.html#currentTransaction">currentTransaction</a> as complete (<a href="Transaction.html#isComplete">Transaction.isComplete</a>),
we add the <a href="Transaction.html">Transaction</a> to the <a href="UndoManager.html#history">history</a> list,
and we return true.
Committing a transaction when there have been some undos without corresponding
redos will throw away the <a href="Transaction.html">Transaction</a>s holding changes that happened
after the current state, before adding the new <a href="Transaction.html">Transaction</a> to the
<a href="UndoManager.html#history">history</a> list.</p>
</div><dl class="tsd-comment-tags"><dt class="">see</dt><dd><p><a href="UndoManager.html#startTransaction">startTransaction</a>, <a href="UndoManager.html#rollbackTransaction">rollbackTransaction</a></p>
</dd></dl></div><h4 class="tsd-parameters-title">Parameters</h4><ul class="tsd-parameters"><li><h5><span class="tsd-flag ts-flagOptional">Optional</span> tname: <span class="tsd-signature-type">string</span></h5><div class="tsd-comment tsd-typography">
<p>a short string describing the transaction;
this is recorded as the <a href="Transaction.html#name">Transaction.name</a> and need not be the same as the string passed to <a href="UndoManager.html#startTransaction">startTransaction</a>.
If the value is an empty string or not supplied, this will use the name given to <a href="UndoManager.html#startTransaction">startTransaction</a>.</p>
</div></li></ul><h4 class="tsd-returns-title">Returns <span class="tsd-signature-type">boolean</span></h4><div><p>true if ending a top-level transaction.</p>
</div></li></ul></section><section class="tsd-panel tsd-member tsd-kind-method tsd-parent-kind-class"><a id="handleChanged" class="tsd-anchor"></a><h3 class="tsd-anchor-link"> handle<wbr/>Changed<a href="#handleChanged" aria-label="Permalink" class="tsd-anchor-icon"><svg xmlns="http://www.w3.org/2000/svg" class="icon icon-tabler icon-tabler-link" viewBox="0 0 24 24" stroke-width="2" stroke="currentColor" fill="none" stroke-linecap="round" stroke-linejoin="round"><path stroke="none" d="M0 0h24v24H0z" fill="none"></path><path d="M10 14a3.5 3.5 0 0 0 5 0l4 -4a3.5 3.5 0 0 0 -5 -5l-.5 .5"></path><path d="M14 10a3.5 3.5 0 0 0 -5 0l-4 4a3.5 3.5 0 0 0 5 5l.5 -.5"></path></svg></a></h3><ul class="tsd-signatures tsd-kind-method tsd-parent-kind-class"><li class="tsd-signature tsd-kind-icon">handle<wbr/>Changed<span class="tsd-signature-symbol">(</span>e<span class="tsd-signature-symbol">: </span><a href="ChangedEvent.html" class="tsd-signature-type" data-tsd-kind="Class">ChangedEvent</a><span class="tsd-signature-symbol">)</span><span class="tsd-signature-symbol">: </span><span class="tsd-signature-type">void</span></li></ul><ul class="tsd-descriptions"><li class="tsd-description"><div class="tsd-comment tsd-typography">
<p>Maybe record a <a href="ChangedEvent.html">ChangedEvent</a> in the <a href="UndoManager.html#currentTransaction">currentTransaction</a>.
This calls <a href="UndoManager.html#skipsEvent">skipsEvent</a> to see if this should ignore the change.
If <a href="UndoManager.html#skipsEvent">skipsEvent</a> returns false, this creates a copy of the <a href="ChangedEvent.html">ChangedEvent</a>
and adds it to the <a href="UndoManager.html#currentTransaction">currentTransaction</a>.
If there is no <a href="UndoManager.html#currentTransaction">currentTransaction</a>, this first creates and remembers it.</p>
<div><p>This method always ignores all changes while performing
an <a href="UndoManager.html#undo">undo</a> or <a href="UndoManager.html#redo">redo</a>.
This method is also a no-op if <a href="UndoManager.html#isEnabled">isEnabled</a> is false.</p>
</div></div><h4 class="tsd-parameters-title">Parameters</h4><ul class="tsd-parameters"><li><h5>e: <a href="ChangedEvent.html" class="tsd-signature-type" data-tsd-kind="Class">ChangedEvent</a></h5><div class="tsd-comment tsd-typography">
<p>a <a href="ChangedEvent.html">ChangedEvent</a>.</p>
</div></li></ul><h4 class="tsd-returns-title">Returns <span class="tsd-signature-type">void</span></h4></li></ul></section><section class="tsd-panel tsd-member tsd-kind-method tsd-parent-kind-class"><a id="redo" class="tsd-anchor"></a><h3 class="tsd-anchor-link"> redo<a href="#redo" aria-label="Permalink" class="tsd-anchor-icon"><svg xmlns="http://www.w3.org/2000/svg" class="icon icon-tabler icon-tabler-link" viewBox="0 0 24 24" stroke-width="2" stroke="currentColor" fill="none" stroke-linecap="round" stroke-linejoin="round"><path stroke="none" d="M0 0h24v24H0z" fill="none"></path><path d="M10 14a3.5 3.5 0 0 0 5 0l4 -4a3.5 3.5 0 0 0 -5 -5l-.5 .5"></path><path d="M14 10a3.5 3.5 0 0 0 -5 0l-4 4a3.5 3.5 0 0 0 5 5l.5 -.5"></path></svg></a></h3><ul class="tsd-signatures tsd-kind-method tsd-parent-kind-class"><li class="tsd-signature tsd-kind-icon">redo<span class="tsd-signature-symbol">(</span><span class="tsd-signature-symbol">)</span><span class="tsd-signature-symbol">: </span><span class="tsd-signature-type">void</span></li></ul><ul class="tsd-descriptions"><li class="tsd-description"><div class="tsd-comment tsd-typography">
<p>After an <a href="UndoManager.html#undo">undo</a>, re-perform the changes in <a href="UndoManager.html#transactionToRedo">transactionToRedo</a>.
<a href="UndoManager.html#canRedo">canRedo</a> must be true for this method to have any effect.</p>
<div><p>This is called by <a href="CommandHandler.html#redo">CommandHandler.redo</a>.</p>
<p>This will raise a "StartingRedo" <a href="ChangedEvent.html">ChangedEvent</a> of type <a href="ChangedEvent.html#static-Transaction">ChangedEvent.Transaction</a>,
perform the <a href="Transaction.html#redo">Transaction.redo</a> on the <a href="UndoManager.html#transactionToRedo">transactionToRedo</a>, and then
raise a "FinishedRedo" <a href="ChangedEvent.html">ChangedEvent</a> of type <a href="ChangedEvent.html#static-Transaction">ChangedEvent.Transaction</a>.
The two ChangedEvents are to let model listeners know that a redo is about to take place
and that it just finished.
<a href="UndoManager.html#isUndoingRedoing">isUndoingRedoing</a> will temporarily be set to true during this operation.</p>
</div></div><h4 class="tsd-returns-title">Returns <span class="tsd-signature-type">void</span></h4></li></ul></section><section class="tsd-panel tsd-member tsd-kind-method tsd-parent-kind-class"><a id="removeModel" class="tsd-anchor"></a><h3 class="tsd-anchor-link"> remove<wbr/>Model<a href="#removeModel" aria-label="Permalink" class="tsd-anchor-icon"><svg xmlns="http://www.w3.org/2000/svg" class="icon icon-tabler icon-tabler-link" viewBox="0 0 24 24" stroke-width="2" stroke="currentColor" fill="none" stroke-linecap="round" stroke-linejoin="round"><path stroke="none" d="M0 0h24v24H0z" fill="none"></path><path d="M10 14a3.5 3.5 0 0 0 5 0l4 -4a3.5 3.5 0 0 0 -5 -5l-.5 .5"></path><path d="M14 10a3.5 3.5 0 0 0 -5 0l-4 4a3.5 3.5 0 0 0 5 5l.5 -.5"></path></svg></a></h3><ul class="tsd-signatures tsd-kind-method tsd-parent-kind-class"><li class="tsd-signature tsd-kind-icon">remove<wbr/>Model<span class="tsd-signature-symbol">(</span>model<span class="tsd-signature-symbol">: </span><a href="Model.html" class="tsd-signature-type" data-tsd-kind="Class">Model</a><span class="tsd-signature-symbol">)</span><span class="tsd-signature-symbol">: </span><span class="tsd-signature-type">void</span></li></ul><ul class="tsd-descriptions"><li class="tsd-description"><div class="tsd-comment tsd-typography">
<p>Inform this UndoManager that it will no longer be receiving <a href="ChangedEvent.html">ChangedEvent</a>s
when the given <a href="Model.html">Model</a> is changed.
The model will no longer receive notifications about transactions and undo or redo operations.</p>
<div><p>You should not call this method during a transaction.
If you call this method between transactions when there is a transaction history,
you should be careful that there are no <a href="ChangedEvent.html">ChangedEvent</a>s referring to that model in any <a href="Transaction.html">Transaction</a>s.</p>
</div><dl class="tsd-comment-tags"><dt class="">see</dt><dd><p><a href="UndoManager.html#models">models</a>, <a href="UndoManager.html#addModel">addModel</a></p>
</dd></dl></div><h4 class="tsd-parameters-title">Parameters</h4><ul class="tsd-parameters"><li><h5>model: <a href="Model.html" class="tsd-signature-type" data-tsd-kind="Class">Model</a></h5><div class="tsd-comment tsd-typography">
<p>A <a href="Model.html">Model</a> that this UndoManager should no longer manage.</p>
</div></li></ul><h4 class="tsd-returns-title">Returns <span class="tsd-signature-type">void</span></h4></li></ul></section><sectio