31 lines
1.3 KiB
TypeScript
31 lines
1.3 KiB
TypeScript
export const cityTimezonesHandler = async () => {
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/**
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* Lazy loads third party dependency to avoid loading 1.5Mb for ALL tRPC procedures.
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* Thanks @roae for the tip 🙏
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**/
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const allCities = await import("city-timezones").then((mod) => mod.cityMapping);
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/**
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* Filter out all cities that have the same "city" key and only use the one with the highest population.
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* This way we return a new array of cities without running the risk of having more than one city
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* with the same name on the dropdown and prevent users from mistaking the time zone of the desired city.
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*/
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const topPopulatedCities: { [key: string]: { city: string; timezone: string; pop: number } } = {};
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allCities.forEach((city) => {
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const cityPopulationCount = city.pop;
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if (
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topPopulatedCities[city.city]?.pop === undefined ||
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cityPopulationCount > topPopulatedCities[city.city].pop
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) {
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topPopulatedCities[city.city] = { city: city.city, timezone: city.timezone, pop: city.pop };
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}
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});
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const uniqueCities = Object.values(topPopulatedCities);
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/** Add specific overries in here */
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uniqueCities.forEach((city) => {
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if (city.city === "London") city.timezone = "Europe/London";
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if (city.city === "Londonderry") city.city = "London";
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});
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return uniqueCities;
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};
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