Statistics

Statistics in ESP-DASH allow you to display key values and metrics on your dashboard in a dedicated “Statistics” tab. They are ideal for showing device information, sensor readings, or any other single data point that you want to highlight.

Types

ESPDash provides two types of statistics widget:

Statistic Value: For displaying a static value that you manually update.
Statistic Provider: For displaying a value that is updated automatically by a provided function.

Initializing Statistics

Statistics are initialized with the ESPDash instance and a name (or key). The name is used to identify the statistic on the dashboard.

Statistic Value


dash::StatisticValue<const char*> hardwareStat(dashboard, "Hardware");
dash::StatisticValue<uint32_t> freeHeapStat(dashboard, "Free Heap");

Statistic Provider


dash::StatisticProvider<uint32_t> heapProvider(dashboard, "Free Heap (SRAM)");

Setters

Setting Value (Statistic Value)

For StatisticValue, you can update the value using the setValue() method. This method returns true if the value has changed, and false otherwise.


hardwareStat.setValue("ESP32");
freeHeapStat.setValue(ESP.getFreeHeap());

Setting Provider (Statistic Provider)

For StatisticProvider, you set a callback function using setProvider(). This function will be called by ESP-DASH to get the latest value for the statistic.


heapProvider.setProvider([]() {
  return ESP.getFreeHeap();
});

Reference

Here’s an example demonstrating the initialization and usage of both StatisticValue and StatisticProvider:


...
 
// Statistic Value
dash::StatisticValue<const char*> hardware(dashboard, "Hardware");
dash::StatisticValue<dash::string> sdkVersion(dashboard, "SDK Version");
 
// Statistic Provider
dash::StatisticProvider<uint32_t> freeHeap(dashboard, "Free Heap (SRAM)");
 
void setup() {
  ...
 
  // Set values for Statistic Value
  hardware.setValue("my-custom-hardware");
  sdkVersion.setValue(ESP.getSdkVersion());
 
  // Set provider for Statistic Provider
  freeHeap.setProvider([]() {
    return ESP.getFreeHeap();
  });
 
}
 
void loop() {
  // You don't need to manually update StatisticProvider values in loop
  // as they are fetched on-demand when the dashboard refreshes.
  // -----
  // However, if using StatisticValue then you will have to
  // manually update whenever the data changes.
  // For example:
  // if (some_condition) {
  //   hardware.setValue("New Hardware Value");
  // }
}