如何在节点红色中设置环境变量？答案

【问题标题】：How to set environment variables in node red?如何在节点红色中设置环境变量？
【发布时间】：2018-09-24 18:01:04
【问题描述】：

我是使用 Node-Red 进行开发的新手，正在寻找一种将值集作为环境变量导入我的流程的方法。

非常感谢您对此提供任何帮助。

【问题讨论】：

标签： javascript environment-variables node-red

【解决方案1】：

从 node-RED 0.19 版开始，将环境变量导入流更容易。

来源：https://nodered.org/blog/2018/08/14/version-0-19-released

示例：读取环境变量 COMPUTERNAME，使用更改节点：

[{"id":"d17299e5.9ff148","type":"tab","label":"Flow 5","disabled":false,"info":""},{"id":"d66f687a.d01248","type":"change","z":"d17299e5.9ff148","name":"","rules":[{"t":"set","p":"payload","pt":"msg","to":"COMPUTERNAME","tot":"env"}],"action":"","property":"","from":"","to":"","reg":false,"x":380,"y":140,"wires":[["67cb1bc6.0b3724"]]},{"id":"578fe08e.8f056","type":"inject","z":"d17299e5.9ff148","name":"","topic":"","payload":"","payloadType":"date","repeat":"","crontab":"","once":false,"onceDelay":0.1,"x":160,"y":140,"wires":[["d66f687a.d01248"]]},{"id":"67cb1bc6.0b3724","type":"debug","z":"d17299e5.9ff148","name":"","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"false","x":580,"y":140,"wires":[]}]

【讨论】：

【解决方案2】：

您可以使用process.env 对象设置环境变量。即：

process.env.SOME_VAR = "VALUE";

并获取值：

var someData = process.env.SOME_VAR || "default value";

【讨论】：

【解决方案3】：

除了AIOT MAKER建议的方法之外，还可以使用$env()函数在表达式中访问环境变量。

【讨论】：