Mailspring/docs/TaskQueue.html

---
layout: docs
title: TaskQueue
edit_url: "https://github.com/nylas/N1/blob/master/src/flux/stores/task-queue.coffee"
---

<h2>Summary</h2>

<div class="markdown-from-sourecode">
  <p><p>The TaskQueue is a Flux-compatible Store that manages a queue of <a href='task.html'>Task</a>
objects. Each <a href='task.html'>Task</a> represents an individual API action, like sending a draft
or marking a thread as &quot;read&quot;. Tasks optimistically make changes to the app&#39;s
local cache and encapsulate logic for performing changes on the server, rolling
back in case of failure, and waiting on dependent tasks.</p>
<p>The TaskQueue is essential to offline mode in N1. It automatically pauses
when the user&#39;s internet connection is unavailable and resumes when online.</p>
<p>The task queue is persisted to disk, ensuring that tasks are executed later,
even if the user quits N1.</p>
<p>The TaskQueue is only available in the app&#39;s main window. Rather than directly
queuing tasks, you should use the <a href='actions.html'>Actions</a> to interact with the <a href='taskqueue.html'>TaskQueue</a>.
Tasks queued from secondary windows are serialized and sent to the application&#39;s
main window via IPC.</p>
<h2 id="queueing-a-task">Queueing a Task</h2>
<pre><code class="lang-coffee"><span class="hljs-keyword">if</span> <span class="hljs-property">@_thread</span> &amp;&amp; <span class="hljs-property">@_thread</span>.unread
  Actions.queueTask(<span class="hljs-keyword">new</span> ChangeStarredTask(<span class="hljs-attribute">thread</span>: <span class="hljs-property">@_thread</span>, <span class="hljs-attribute">starred</span>: <span class="hljs-literal">true</span>))
</code></pre>
<h2 id="dequeueing-a-task">Dequeueing a Task</h2>
<pre><code class="lang-coffee"><span class="hljs-tag">Actions</span><span class="hljs-class">.dequeueMatchingTask</span>(<span class="hljs-rules">{
  <span class="hljs-rule"><span class="hljs-attribute">type</span>:<span class="hljs-value"> <span class="hljs-string">'FileUploadTask'</span>,
  matching: {
    filePath: uploadData.filePath
  }
})</span></span></span>
</code></pre>
<h2 id="creating-tasks">Creating Tasks</h2>
<p>Support for creating custom <a href='task.html'>Task</a> subclasses in third-party packages is coming soon.
This is currently blocked by the ActionBridge, which is responsible for sending actions
between windows, since it&#39;s JSON serializer is not extensible.</p>
</p>
</div>

<ul>
</ul>





    <h3>Instance Methods</h3>

    <h4 id=findTask class="function-name">
      findTask(<span class="args"><span class="arg">type</span><span class="arg">matching</span></span>) <a href="#findTask" class="link"></a>
    </h4>

    <div class="function-description markdown-from-sourecode">
      <p></p>
    </div>

        <strong>Parameters</strong>
        <table class="arguments">
            <tr>
              <th>Argument</th>
              <th>Description</th>
            </tr>
            <tr>
              <td style="width:15%;">
                <em>type</em>
              </td>
              <td class="markdown-from-sourecode">

                <p>The string name of the task class, or the Task class itself. (ie: {SaveDraftTask} or &#39;SaveDraftTask&#39;)</p>

              </td>
            </tr>
            <tr>
              <td style="width:15%;">
                <em>matching</em>
              </td>
              <td class="markdown-from-sourecode">

                <p>Optional An <a href='https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/object'>Object</a> with criteria to pass to _.isMatch. For a  SaveDraftTask, this could be {draftClientId: &quot;123123&quot;}</p>

              </td>
            </tr>
        </table>

        <strong>Returns</strong>
        <table class="arguments">
          <tr>
            <th>Return Values</th>
          </tr>
          <tr><td class="markdown-from-sourecode"><p>Returns an existing task in the queue that matches the type you provide,
    and any other match properties. Useful for checking to see if something, like
    a &quot;SendDraft&quot; task is in-flight.</p>
    </td></tr>
          <tr><td class="markdown-from-sourecode"><p>Returns a matching <a href='task.html'>Task</a>, or null.</p>
    </td></tr>
        </table>