cap:battery-level - monitor battery level

The battery-level capability is used for things that have a battery that can be monitored. Sometimes this capability is combined with charging-state if the thing also can report when it is being charged.

if(thing.matches('cap:battery-level')) {
        console.log('Current battery level:', await thing.batteryLevel());
}

API

batteryLevel()

Get the current battery level as a percentage between 0 and 100.

Returns:Promise that resolves to the battery level in percent.

Example:

thing.batteryLevel()
        .then(level => ...)
        .catch(...);

const level = await thing.batteryLevel();

Events

batteryLevelChanged

The current battery level has changed. Payload will be the new battery level as a percentage.

thing.on('batteryLevelChanged', batteryLevel => console.log('Battery level is now:', batteryLevel));

Protected methods

updateBatteryLevel(batteryLevel)

Update the current battery level. Should be called whenever a change in battery level is detected.

Arguments:

• batteryLevel (percentage) – The new battery level. Will be converted to a percentage.

Example:

this.updateBatteryLevel(20);
this.updateBatteryLevel('10');

Implementing capability

When implementing this capability the implementor needs to call updateBatteryLevel whenever the battery level changes.

const { Thing, BatteryLevel } = require('abstract-things');

class Example extends Thing.with(BatteryLevel) {

        initCallback() {
                return super.initCallback()
                        .then(readBatteryLevelSomehow)
                        .then(batteryLevel => {
                                this.updateBatteryLevel(batteryLevel);
                        });
        }

}