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Extract instead of duplicating

@RiccardoOdone•Suggest a tip•

Use Extract to derive a type from another one and maintain a single point-of-truth.

type Keys = "commentId" | "userId" | "rating"
type Refs = "commentId" | "userId"
// ⛔️ Need to keep Keys and Refs in sync

type Keys = "commentId" | "userId" | "rating"
type Refs = Extract<Keys, `${string}Id`>
//   ^? "commentId" | "userId"
Type-safe carouselDo not throwFilter using a type assertionUse precise typesType-safe string templatingEnumerating a union typeNumbers with unitsZero nullEnumerating statusesAnd typesAvoiding window as anyUse descriptive valuesCheck authorization with typesExtract union types from record typesKeep in sync with conditional typesType-safe pickPass arguments by namePick instead of duplicatingPrevent mutationsType aliasesModel with different typesPrefer static types over testsPush conditionals downType-level functionsCheck Authorization With Types (again)From Union to TupleLimit typesLaser-focused typesCallable typesPartial considered harmfulSatisfy typesWTH?!Parse, don't castNarrow typesFetch footgunModel with different types (2)Polymorphic typesParse, don't cast (again)Type-safe envObject vs Recordconst Type ParametersDigType checksExpand intellisenseNumbers with units (2)Unchecked indexed accessExtract instead of duplicating

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