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const Type Parameters

@RiccardoOdone•Suggest a tip•

Make TypeScript v5+ infer the more specific type (instead of the most generic).

const first = (xs: unknown[]) => xs[0]
pick(["a", "b"])
// ^? unknown

const first = (xs: any[]) => xs[0]
pick(["a", "b"])
// ^? any

const first = <T>(xs: T[]) => xs[0]
pick(["a", "b"])
// ^? string

const pick = <const T>(xs: T[]) => xs[0]

pick(["a", "b"])
// ^? "a" | "b"
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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