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Using fp-ts for Functional Programming in TypeScript

Solution Review: Create a Mini DSL

Explore how to build a mini domain-specific language (DSL) in TypeScript using fp-ts. Learn to implement functions like createFlight that validate parameters and use exhaustive checks to handle arrival and departure data effectively.

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Solution

TypeScript 3.3.4
const createFlight = (typeOfFlight: KindOfFlight, date: Date) => (airplane: Airplane): O.Option<Flight> => {
    if (!typeOfFlight || !date || !airplane) {
        return O.none;
    }
    switch (typeOfFlight) {
        case 'ARRIVAL': {
            return O.some({
                type: 'Arrival',
                arrivalTime: date,
                airplane,
            });
        }
        case 'DEPARTURE': {
            return O.some({
                type: 'Departure',
                departureTime: date,
                airplane,
            });
        }
        default:
            const _exhaustiveCheck: never = typeOfFlight;
            return _exhaustiveCheck;
    }
};
console.log(createFlight("ARRIVAL",new Date())({seats:100}));

Explanation

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