13 lines
476 B
TypeScript
13 lines
476 B
TypeScript
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type PropertiesThatCanBeUndefined<T extends Record<string, unknown>> = {
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[Key in keyof T]: undefined extends T[Key] ? Key : never;
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}[keyof T];
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/**
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* OptionalIfCanBeUndefined<{ p1: string | undefined; p2: string; }>
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* is
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* { p1?: string | undefined; p2: string }
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*/
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export type OptionalIfCanBeUndefined<T extends Record<string, unknown>> = {
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[K in PropertiesThatCanBeUndefined<T>]?: T[K];
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} & { [K in Exclude<keyof T, PropertiesThatCanBeUndefined<T>>]: T[K] };
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