Events

@Injectable
class StockPriceEmitter {
	// We create the emitter when class gets instantiated
	private emitter = std.createChannelEmitter<number>('apple');

	emit() {
		const randomPrice = Math.random()*300;
		this.emitter.emit(randomPrice);
	}
}

@Injectable
class AppleAverageStockPrice {
	MAX_STORAGE = 10;
	private storedPrices: number[] = [];

	@Show
	averagePrice: number = 0;

	constructor() {
		// We register our listener at the time of instantiation
		std.registerChannelListener(
			'apple',
			std.flow("Calculate Average Apple Stock price", this).updateAverage,
		);
	}

	private addToStoredPrices(price: number) {
		if(this.storedPrices.length >= this.MAX_STORAGE) {
			this.storedPrices.splice(0, 1);
		}

		this.storedPrices.push(price);
	}

	updateAverage(price: number) {
		this.addToStoredPrices(price);

		const averagePrice = this.storedPrices.reduce((acc, cur) => acc+cur, 0) / this.storedPrices.length;
		this.averagePrice = Math.round(averagePrice);
	}
}