node-red/packages/node_modules/@node-red/nodes/locales/en-US/common/25-catch.html

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<script type="text/html" data-help-name="catch">
    <p>Catch errors thrown by nodes on the same tab.</p>
    <h3>Outputs</h3>
    <dl class="message-properties">
        <dt>error.message <span class="property-type">string</span></dt>
        <dd>the error message.</dd>
        <dt>error.source.id <span class="property-type">string</span></dt>
        <dd>the id of the node that threw the error.</dd>
        <dt>error.source.type <span class="property-type">string</span></dt>
        <dd>the type of the node that threw the error.</dd>
        <dt>error.source.name <span class="property-type">string</span></dt>
        <dd>the name, if set, of the node that threw the error.</dd>
    </dl>
    <h3>Details</h3>
    <p>If a node throws an error whilst handling a message, the flow will typically
       halt. This node can be used to catch those errors and handle them with a
       dedicated flow.</p>
    <p>By default, the node will catch errors thrown by any node on the same tab. Alternatively
    it can be targetted at specific nodes, or configured to only catch errors that
    have not already been caught by a 'targeted' catch node.</p>
    <p>When an error is thrown, all matching catch nodes will receive the message.</p>
    <p>If an error is thrown within a subflow, the error will get handled by any
       catch nodes within the subflow. If none exists, the error will be propagated
       up to the tab the subflow instance is on.</p>
   <p>If the message already has a <code>error</code> property, it is copied to <code>_error</code>.</p>
</script>