Ledger- Set specific ledger instance data

Cloud
1

I've been trying out the Ledger, and I've encountered a situation where I want to change only a specific variable, such as tempHighThreshold , without having to replace the entire set of data keys.

Currently, the workaround involves maintaining a separate cloud ledger for these "static" variables. I believe it would be highly beneficial to have an API that allows for partial updates—essentially the ability to modify individual key-based elements within the instance data instead of having to replace the whole data structure every time.

Here’s an example of my data structure for reference:

{
  "instance": {
    "data": {
      "tempHighThreshold": <tempHighThreshold>,
      "tempLowThreshold": <tempLowThreshold>,
      "tempAlertInterval": <tempAlertInterval>,
      "tempAlertsEnabled": <tempAlertsEnabled>,
      "usesFahrenheit": <usesFahrenheit>,
      "lastTempAlertTime": <lastTempAlertTime>
    }
  }
}

I am using Logic to read the temperature data and send a notification through web-hooks if the temperature is outside of the threshold, is enabled, and has not alerted the user within a time interval. The specific issue is lastTempAlertTime is set using the Logic function. When the user updates the settings, the lastTempAlertTime is reset

Update: I have been able to use a function such as

    variablesLedger.set({
        ...variables,  // Preserve existing variables
        lastStatus: status,
        lastStatusTime: now
    });

within Logic to preserve variables in the ledger.

2

From Logic, just use set with the merge option, as in:

ownerLedger.set(newData, Particle.MERGE);