channel.hasSubscribers

• 返回：<boolean> 如果有活跃的订阅者

检查此通道是否有活跃的订阅者。如果你要发送的消息准备起来可能很昂贵，这会很有用。

【Check if there are active subscribers to this channel. This is helpful if the message you want to send might be expensive to prepare.】

此 API 是可选的，但在从对性能极其敏感的代码发布消息时非常有用。

【This API is optional but helpful when trying to publish messages from very performance-sensitive code.】

import diagnostics_channel from 'node:diagnostics_channel';

const channel = diagnostics_channel.channel('my-channel');

if (channel.hasSubscribers) {
  // There are subscribers, prepare and publish message
}const diagnostics_channel = require('node:diagnostics_channel');

const channel = diagnostics_channel.channel('my-channel');

if (channel.hasSubscribers) {
  // There are subscribers, prepare and publish message
}拷贝