50 lines
1.5 KiB
TypeScript
50 lines
1.5 KiB
TypeScript
import { fetchJson, maybe } from "../http";
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import type { AirQuality } from "../types";
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/**
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* Air quality from Open-Meteo's free air-quality API (CAMS data), used for
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* every provider so the AQI always means the same thing.
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* Docs: https://open-meteo.com/en/docs/air-quality-api
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*
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* The same call also tells us the location's IANA time zone, which some
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* providers (Tomorrow.io, OpenWeather free) don't give us.
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*/
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interface AirQualityResponse {
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timezone: string;
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current: {
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us_aqi: number | null;
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pm2_5: number | null;
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pm10: number | null;
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ozone: number | null;
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nitrogen_dioxide: number | null;
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};
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}
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export interface LocalContext {
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timeZone: string;
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airQuality: AirQuality | null;
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}
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export async function getLocalContext(lat: number, lon: number): Promise<LocalContext> {
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const params = new URLSearchParams({
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latitude: String(lat),
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longitude: String(lon),
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current: "us_aqi,pm2_5,pm10,ozone,nitrogen_dioxide",
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timezone: "auto",
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});
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const data = await fetchJson<AirQualityResponse>(
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`https://air-quality-api.open-meteo.com/v1/air-quality?${params}`,
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"Open-Meteo air quality",
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{ cacheSeconds: 1800 }, // air quality updates hourly at most
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);
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const c = data.current;
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return {
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timeZone: data.timezone,
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airQuality:
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c.us_aqi === null
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? null
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: { usAqi: Math.round(c.us_aqi), pm25: maybe(c.pm2_5), pm10: maybe(c.pm10), ozone: maybe(c.ozone), no2: maybe(c.nitrogen_dioxide) },
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};
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}
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