Getting Data from a String

General
1

I need some help! I am not a developer but I have used node red for a solar monitor and it is working great. I have purchased a WiFi temperature monitor that has an API, which it is giving me in a string format (See Below). I want to take the Field8 Value which is 40 and put it in a gauge and I dont have any idea where to start!

Any help would be hugely appreciated.

"{"field3":{"value":0,"created_at":"2019-05-09T21:59:05Z","net":"0"},"field1":{"value":24.081406,"created_at":"2019-05-13T13:44:16Z"},"field2":{"value":31,"created_at":"2019-05-13T13:44:16Z"},"field4":{"value":3.114682,"created_at":"2019-05-13T12:59:04Z"},"field5":{"value":-35,"created_at":"2019-05-13T13:44:14Z"},"field8":{"value":40,"created_at":"2019-05-13T13:44:11Z","net":"1"}}"

2

See this recent thread... Access a value on message
(including the bits at the end)

3

If the data type being returned is a JSON string (as it appears in your post), you should pass it to the json node, set to output a JS Object. Then I would wire this to a change node, and use the JSONata expression payload.field8.value to extract just that number 40.

The change node's JSONata expression editor even has a built-in "tester" panel, so you can take your actual data, paste it into the lower-left window as the payload value, and see the results of your expression in the lower-right window as you type the expression:

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Note that the correct option for entering JSONata expressions is the J: pulldown, not {}

4

Perfect that worked a treat thank you.