line-generation.ts

for (const [stoppingPattern, trips] of tripsByStoppingPattern) {
    const lines = linesByStoppingPattern.get(stoppingPattern, []);

    for (const trip of trips) {
        this.getLineForTrip(trip, lines).match({
            some: line => line.add(trip),
            none: () => lines.push(new Line([trip]))
        });

        linesByStoppingPattern = linesByStoppingPattern.set(stoppingPattern, lines);
    }
}