In plot.ly, you are able to add a listener for legend click events. How can I find out which trace in the legend I clicked? For a more concrete example, suppose I have two traces (trace0, trace1) in a line graph. When the user clicks trace0 in the legend, I want to display an alert saying "trace0". Similarly, when the user clicks trace1 in the legend, I want an alert saying something different. I can make alerts just fine but I can't find any documentation on how plot.ly identifies which trace is clicked in the legend. Any help?
According to the documentation about Event Handlers you can use data, which contains information about the event.
var trace1 = {
x: [1, 2, 3, 4],
y: [10, 15, 13, 17],
type: 'scatter'
};
var trace2 = {
x: [1, 2, 3, 4],
y: [16, 5, 11, 9],
type: 'scatter'
};
var data = [trace1, trace2];
Plotly.newPlot('myDiv', data);
var myPlot = document.getElementById('myDiv');
myPlot.on('plotly_click', function(data) {
// get event information from data
console.log(data);
});