negate() function

述語関数の反対の結果を返す関数を作成します。

Signature:

declare function negate<T, N extends T>(
  predicate: (input: T) => input is N,
): (input: T) => input is Exclude<T, N>;

Example

const isDefined: (input: string | undefined) => input is string = negate(isUndefined)<string | undefined>

const isDefined: (input: unknown) => boolean = negate((input) => input === undefined)

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