Find why stop does not remove the listener registered by start.
JavaScript
'use strict';
class Dashboard {
constructor(bus) {
this.bus = bus;
this.total = 0;
}
render(value) {
this.total += value;
}
start() {
this.bus.on('data', this.render.bind(this));
}
stop() {
this.bus.off('data', this.render.bind(this));
}
}