- Node
- A Node is the basic building block of a flow.
节点通过从流程中的前一个节点接收消息，或通过等待某些外部事件（如传入的HTTP请求、定时器或GPIO硬件变化）来触发。它们处理该消息或事件，然后可能会向流程中的下一个节点发送消息。
一个节点最多可以有一个输入端口和任意数量的输出端口。
- Configuration node
- A Configuration (config) Node is a special type of node that holds reusable
configuration that can be shared by regular nodes in a flow.
例如，MQTT输入和输出节点使用MQTT代理配置节点来表示与MQTT代理的共享连接。
配置节点不会显示在主工作区中，但可以通过打开配置节点侧边栏查看。
- Flow
- A Flow is represented as a tab within the editor workspace and is the main way to
organise nodes.
术语“flow”也常用于非正式地描述一组相互连接的节点。因此，一个flow（标签页）可以包含多个flows（相互连接的节点组）。
- Context
- Context is a way to store information that can be shared between nodes without
using the messages that pass through a flow.
上下文有三种类型；
- 节点 - 仅对设置该值的节点可见
- 流程 - 对同一流程（或编辑器中的标签页）上的所有节点可见
- 全局 - 对所有节点可见
默认情况下，Node-RED使用内存中的上下文存储，因此值不会在重启时保存。可以配置为使用基于文件系统的存储，使值持久化。也可以插入替代的存储插件。
- Message
- Messages are what pass between the nodes in a flow. They are plain JavaScript
objects that can have any set of properties. They are often referred to as
msg
within the editor.
按照惯例，它们有一个payload属性，包含最有用的信息。
- Subflow
- A Subflow is a collection of nodes that are collapsed into a single node in
the workspace.
它们可用于降低流程的视觉复杂度，或将一组节点打包成可在多处重复使用的组件。
- Wire
- Wires connect the nodes and represent how messages pass through the flow.
- Palette
- The Palette is on the left of the editor and lists of the nodes that are available
to use in flows.
可以通过命令行或调色板管理器将额外节点安装到调色板中。
- Workspace
- The Workspace is the main area where flows are developed by dragging nodes
from the palette and wiring them together.
工作区顶部有一排标签页；每个流程以及已打开的任何子流程各有一个标签。
- The sidebar contains panels that provide a number of useful tools within the
editor. These include panels to view more information and help about a node,
to view debug message and to view the flow’s configuration nodes.
