Function validateString

Returns a valid string from the supplied value, ensuring the supplied value is a string that conforms to the given checkFn.

Throws

LisnUsageError If the value is invalid.

  • validateString<T extends string = string>(
        key: string,
        value: unknown,
        checkFn?: (value: string) => value is T,
    ): undefined | T

    Type Parameters

    • T extends string = string

    Parameters

    • key: string
    • value: unknown
    • OptionalcheckFn: (value: string) => value is T

      If given and the supplied value is a string, then it is called with the value as a single argument. It must return true if the value is valid and false otherwise. If it is not given, then any literal string is accepted.

    Returns undefined | T

    undefined if the input is nullish.

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