rxjs/operators#mergeScan TypeScript Examples

The following examples show how to use rxjs/operators#mergeScan. You can vote up the ones you like or vote down the ones you don't like, and go to the original project or source file by following the links above each example. You may check out the related API usage on the sidebar.
Example #1
Source File: RestApi.ts    From majsoul-api with MIT License 5 votes vote down vote up 
private async getLeaguePhaseData({
		contest,
		transitions,
		phases
	}: PhaseInfo): Promise<LeaguePhase<ObjectID>[]> {
		const sessions = (await this.getSessions(contest).pipe(toArray()).toPromise())
			.sort((a, b) => a.scheduledTime - b.scheduledTime);
		return from(phases.concat(null)).pipe(
			pairwise(),
			mergeScan((completePhase, [phase, nextPhase]) => {
				const transition = transitions[phase.index];
				const phaseSessions = sessions.filter(
					session =>
						session.scheduledTime >= phase.startTime
						&& (nextPhase == null || session.scheduledTime < nextPhase.startTime)
				);
				const startingTotals = {
					...completePhase.sessions[completePhase.sessions.length - 1]?.aggregateTotals ?? {}
				};

				const rankedTeams = Object.entries(startingTotals)
					.map(([team, score]) => ({ team, score }))
					.sort((a, b) => b.score - a.score);

				const allowedTeams = transition.teams?.top
					? rankedTeams.slice(0, transition.teams.top)
						.reduce((total, next) => (total[next.team] = true, total), {} as Record<string, true>)
					: null;

				for (const team of Object.keys(startingTotals)) {
					if (allowedTeams && !(team in allowedTeams)) {
						delete startingTotals[team];
						continue;
					}

					if (transition.score?.half) {
						startingTotals[team] = Math.floor(startingTotals[team] / 2);
					} else if (transition.score?.nil) {
						startingTotals[team] = 0;
					}
				}

				return of({
					...phase,
					sessions: phaseSessions.reduce((total, next) => {
						const aggregateTotals = { ...(total[total.length - 1]?.aggregateTotals ?? startingTotals) };
						const filteredTotals = Object.entries(next.totals)
							.filter(([key]) => !allowedTeams || key in allowedTeams)
							.reduce((total, [key, value]) => (total[key] = value, total), {} as Record<string, number>);

						for (const team in filteredTotals) {
							if (aggregateTotals[team] == null) {
								aggregateTotals[team] = 0;
							}
							aggregateTotals[team] += filteredTotals[team];
						}

						total.push({
							...next,
							totals: filteredTotals,
							aggregateTotals,
						})
						return total;
					}, [] as Session<ObjectID>[]),
					aggregateTotals: startingTotals,
				} as LeaguePhase<ObjectID>);
			}, {
				sessions: [{
					aggregateTotals: (contest.teams ?? []).reduce(
						(total, next) => (total[next._id.toHexString()] = 0, total),
						{} as Record<string, number>
					)
				}]
			} as LeaguePhase<ObjectID>, 1),
			toArray(),
		).toPromise();
	}