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node-red/packages/node_modules/@node-red/nodes/locales/zh-CN/function/10-function.html
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<script type="text/x-red" data-help-name="function">
<p>定义对接收到的消息进行处理的JavaScript代码函数的主体</p>
<p>输入消息在名为<code>msg</code>JavaScript</p>
<p>通常<code>msg</code><code>msg.payload</code></p>
<p>该函数一般会返回一个消息对象或多个消息对象但也可以为了停止流而什么都不返回</p>
<h3>详细</h3>
<p>请参见<a target="_blank" href="https://nodered.org/docs/writing-functions.html">在线文档</a></p>
<h4>传送消息</h4>
<p>要将消息传递到流中的下一个节点请返回消息或调用<code>node.send(messages)</code></p>
<p>它将返回/send:</p>
<ul>
<li>单个消息对象 - 传递给连接到第一个输出的节点</li>
<li>消息对象数组传递给连接到相应输出的节点</li>
</ul>
<p>如果数组元素是数组则将多个消息发送到相应的输出</p>
<p>无论return方法是单个值还是数组元素如果返回值为null则不会发送任何消息</p>
<h4>日志输出和错误处理</h4>
<p>使用以下功能输出日志信息和输出错误</p>
<ul>
<li><code>node.log("Log message")</code></li>
<li><code>node.warn("Warning")</code></li>
<li><code>node.error("Error")</code></li>
</ul>
</p>
<p>使用catch节点可以进行错误处理 要由catch节点处理请将<code>msg</code><code>node.error</code></p>
<pre>node.error("Error",msg);</pre>
<h4>访问节点信息</h4>
<p>您可以使用以下属性来在代码中引用节点ID和名称</p>
<ul>
<li><code>node.id</code> - ID</li>
<li><code>node.name</code> - </li>
</ul>
<h4>使用环境变量</h4>
<p>环境变量可以通过<code>env.get("MY_ENV_VAR")</code>访</p>
</script>