Let's break down what your code is doing step-by-step: 1. **Create...

Let's break down what your code is doing step-by-step:

1. Create a Set (storeSet):

   const storeSet = new Set();
   

   A Set is created to store unique values of the metric.label.store extracted from seriesObj.

2. Iterate through context.panel.data.series:

   context.panel.data.series.forEach((seriesObj) => {
       storeSet.add(seriesObj.meta.custom.labels["metric.label.store"]);
       console.log(seriesObj.meta.custom.labels["metric.label.store"]);
   });
   

   For each series object in context.panel.data.series:

   • The metric.label.store value from meta.custom.labels is added to the storeSet.
   • This ensures only unique values are added since Set automatically enforces uniqueness.
   • The extracted metric.label.store value is logged to the console.

3. Log the Set values:

   console.log(storeSet);
   

   The Set (storeSet) is logged for debugging purposes.

4. Convert the Set to an Array:

   const storesArray = Array.from(storeSet);
   

   The storeSet is converted into an array (storesArray) so it can later be passed as a value to the chart's click handler.

5. Add an event listener to the chart's mouseover event:

   context.panel.chart.on("mouseover", (params) => {
       context.grafana.locationService.partial({ "var-query0": storesArray }, true);
   });
   

   This line adds a mouseover event listener to a chart.

   • When the mouseover event occurs on the chart, the code updates a variable var-query0 in the Grafana URL with the storesArray as a query parameter.
   • The true parameter at the end indicates that it should replace or merge the parameter in the URL.

6. Return the title:

   return {
       'title': { "text": "update" }
   };
   

   Finally, the function returns an object with the chart's title set to "update".

Why might the text not update on click?

The text (title) defined here ("update") is hardcoded in the return statement. Since there is nothing in your code that dynamically updates this title value when you interact with the chart, clicking or triggering the mouseover event won't modify it.

Key reasons:

1. The title "update" is static:
   • The title is defined in the return statement and does not depend on any dynamic parameters or events.
2. No click handler in place:
   • While you are using a mouseover event, the code has no click event listener or logic tied to the title update.
3. No UI-binding updates for the title:
   • Grafana panels generally do not reactively update elements such as titles unless explicitly reinitialized with new parameters. Simply returning an updated title object won't automatically change the title in the UI once it is rendered.

Suggested Fix:

If you want to update the title dynamically (e.g., based on interactions with the chart), you need to explicitly set or render the title in response to the chart's interactions. Here's an example of how you could handle it:

context.panel.chart.on("mouseover", (params) => {
    context.grafana.locationService.partial({ "var-query0": storesArray }, true);

    // Dynamically set chart title
    context.panel.chart.setOption({
        title: { text: `Store Hovered: ${params.name}` }
    });
});

This code extends the mouseover event to dynamically set the chart title using the setOption method (common in libraries like ECharts). Ensure that your chart library supports this method to update the title directly when the mouseover event occurs.