Created
April 10, 2018 07:15
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Result: success/failure type union
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interface IFoo { | |
bar : string; | |
} | |
function validateSomething(obj : IFoo) : Result<string, IFoo> { | |
if (obj.bar.length === 0) { | |
return resultFailure("You must provide at least one object"); | |
} else { | |
return resultSuccess(obj); | |
} | |
} |
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// This is a poor man's "Either", without any monadic capabilities. | |
export interface Success<TValue> { | |
success: true; | |
value: TValue; | |
} | |
export interface Failure<TFailure> { | |
success: false; | |
failure: TFailure; | |
} | |
export type Result<TFailure, TValue> = Failure<TFailure> | Success<TValue>; | |
// Below are some convenience functions to reduce boilerplate, or make it more DSL-y. (Otherwise you might need to cast "true" to "true", instead of letting it be typed to "boolean") | |
export function resultSuccess<T>(value: T): Success<T> { | |
return { | |
success: true, | |
value | |
}; | |
} | |
export function resultFailure<T>(failure: T): Failure<T> { | |
return { | |
success: false, | |
failure | |
}; | |
} |
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