Documentation - Mapped Types

When you don’t want to repeat yourself, sometimes a type needs to be based on another type. Mapped types build on the syntax for index signatures, which are used to declare the types of properties which have not been declared ahead of time:

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Mapped Typeのasを使ってkeyとvalueの参照するtypeをそれぞれ別にできる。 オブジェクトの配列から特定のプロパティをキーに、特定のプロパティーを値にしたオブジェクトを作れる https://x.com/azu_re/status/1806242182376177683