Subscribe To Events

EasyBar widgets become interesting when they react to runtime events.

This guide shows how to subscribe to events and how to think about the payload you receive.

Basic subscription

local battery = easybar.add(easybar.kind.item, "battery_status", {
    position = "right",
    order = 20,
    label = "Battery",
})

battery:subscribe(easybar.events.forced, function()
    battery:set({
        label = "Refreshed",
    })
end)

This attaches one handler to one event token.

Mouse interaction

battery:subscribe(easybar.events.mouse.clicked, function(event)
    if event.button == "left" then
        battery:set({
            label = "Clicked",
        })
    end
end)

The event payload tells you what happened. For mouse events, common fields include:

• event.button
• event.direction
• event.target_widget_id

See Events.

Multiple events

You can subscribe to more than one event at once:

battery:subscribe({
    easybar.events.forced,
    easybar.events.power_source_change,
    easybar.events.charging_state_change,
}, function(event)
    battery:set({
        label = event.name,
    })
end)

This works well when several runtime events should trigger the same refresh logic.

Pattern: separate render from event handling

For non-trivial widgets, it helps to separate state updates from rendering:

local state = {
    connected = false,
}

local vpn = easybar.add(easybar.kind.item, "vpn", {
    position = "right",
    order = 30,
})

local function render()
    vpn:set({
        label = state.connected and "VPN On" or "VPN Off",
    })
end

vpn:subscribe(easybar.events.forced, function()
    render()
end)

vpn:subscribe(easybar.events.mouse.clicked, function(event)
    if event.button == "left" then
        state.connected = not state.connected
        render()
    end
end)

render()

This keeps the event handlers small and makes the widget easier to grow later.

Which events should you use?

• Use runtime events like space_change, app_switch, or volume_change for system-driven updates.
• Use mouse events for interaction on one node.
• Use interval callbacks when the data has no natural runtime event.

Next steps

• Read First Widget if you have not built a basic widget yet.
• Read Events for the full event list and payload types.
• Read Commands if your event handler needs to call shell commands.