TypeScript array with minimum length

Question

How can you create a type in TypeScript that only accepts arrays with two or more elements?

needsTwoOrMore([\"onlyOne\"]) // should have error
needsTwoOrMore         


        

Answer 1

This can be accomplished with a type like:

type ArrayTwoOrMore = {
    0: T
    1: T
} & Array

declare function needsTwoOrMore(arg: ArrayTwoOrMore): void

needsTwoOrMore(["onlyOne"]) // has error
needsTwoOrMore(["one", "two"]) // allowed
needsTwoOrMore(["one", "two", "three"]) // also allowed

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