node-red-contrib-data-view

node-red-contrib-data-view

Node-RED node to preview data with a simple line chart inside the Node-RED flow editor. This node was inspired by the simple image preview node node-red-contrib-image-output.

Currently the node expects the input msg.payload to contain a number value. The node will then create a line chart in the flow editor under the node displaying the values received over time.

NOTE: This node is a work in progress. I expect to add additional chart options, chart types and support different shapes of data. Feedback is welcome.

Installation

Either use the Editor - Menu - Manage Palette - Install option, or run the following npm command in your Node-RED user directory (typically ~/.node-red):

npm i node-red-contrib-data-view

Node usage

This node can be used to view simple line charts inside the Node-RED flow editor as illustrated below.

The following example demonstrates how to inject numbers into the node to generate charts, how to clear a chart, and test node error handling when a non-numeric payload is used in msg.payload.

[{"id":"2cd7059b.70ec6a","type":"data-view","z":"de60a83e.dce718","name":"wide chart","width":"400","height":"160","points":"100","active":true,"passthru":false,"outputs":0,"x":550,"y":120,"wires":[]},{"id":"1459af05.cfcc01","type":"inject","z":"de60a83e.dce718","name":"trigger data","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":true,"onceDelay":0.1,"topic":"","payload":"","payloadType":"date","x":150,"y":120,"wires":[["93544758.228ec8"]]},{"id":"93544758.228ec8","type":"function","z":"de60a83e.dce718","name":"generate values","func":"msg.payload = Math.floor(Math.random() * 100)-50;\nreturn msg;","outputs":1,"noerr":0,"initialize":"","finalize":"","x":360,"y":120,"wires":[["2cd7059b.70ec6a","e2c1381f.9dad28","47a657d1.c696f8"]]},{"id":"8841bc1f.0fee1","type":"debug","z":"de60a83e.dce718","name":"","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"false","statusVal":"","statusType":"auto","x":730,"y":340,"wires":[]},{"id":"a0e15f78.4871c","type":"inject","z":"de60a83e.dce718","name":"clear chart","props":[{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"test","x":160,"y":160,"wires":[["2cd7059b.70ec6a"]]},{"id":"4de026cb.33c388","type":"inject","z":"de60a83e.dce718","name":"send bad data","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"strings can't be graphes","payloadType":"str","x":150,"y":200,"wires":[["2cd7059b.70ec6a"]]},{"id":"e2c1381f.9dad28","type":"data-view","z":"de60a83e.dce718","name":"pass through","width":"300","height":"160","points":"50","active":true,"passthru":true,"outputs":1,"x":550,"y":340,"wires":[["8841bc1f.0fee1"]]},{"id":"47a657d1.c696f8","type":"data-view","z":"de60a83e.dce718","name":"","width":200,"height":160,"active":true,"passthru":false,"outputs":0,"x":320,"y":340,"wires":[]}]

This example flow is also available via the 'Import' menu in the Node-RED flow editor.

Node configuration

Height

The height (in pixels) of the chart.

Width

The width (in pixels) of the chart.

Line points

The number of points to display in the chart before they are dropped. The client side code maintains a circular buffer for each node.

Allow data passthrough

When selected this adds an output wire to the node in order to pass the original message through to a following node.

This performs better than forking the wires, however it does remove the enable/disable button.