Simple Functions for ReadonlyArrays and Chunks

/**
 * Returns true if the provided ReadonlyArray contains duplicates
 * @category utils
 * @since 1.0.0
 */
export const hasDuplicates = <A>(self: ReadonlyArray<A>): boolean =>
    pipe(self, RA.dedupe, (as) => (as.length === self.length ? false : true));

/**
 * Returns true if the provided ReadonlyArray contains duplicates using the provided isEquivalent function
 * @category utils
 * @since 1.0.0
 */
export const hasDuplicatesWith = dual<
    {
        <A>(isEquivalent: (self: A, that: A) => boolean): (self: ReadonlyArray<A>) => boolean;
    },
    {
        <A>(self: ReadonlyArray<A>, isEquivalent: (self: A, that: A) => boolean): boolean;
    }
>(2, <A>(self: ReadonlyArray<A>, isEquivalent: (self: A, that: A) => boolean) =>
    pipe(self, RA.dedupeWith(isEquivalent), (as) => (as.length === self.length ? false : true))
);

/**
 * Looks for elements that fulfill a predicate. Returns `none` in case no element or more than
 * one element is found. Otherwise returns the sole matchning element.
 *
 * @category getters
 * @since 1.0.0
 */
export const findSole = dual<
    {
        <A, B extends A>(
            refinement: (a: A, i: number) => a is B
        ): (self: ReadonlyArray<A>) => O.Option<B>;
        <A>(predicate: (a: A, i: number) => boolean): (self: ReadonlyArray<A>) => O.Option<A>;
    },
    {
        <A, B extends A>(self: ReadonlyArray<A>, refinement: (a: A, i: number) => a is B): O.Option<B>;
        <A>(self: ReadonlyArray<A>, predicate: (a: A, i: number) => boolean): O.Option<A>;
    }
>(2, <A>(self: ReadonlyArray<A>, predicate: (a: A, i: number) => boolean) =>
    pipe(self, RA.filter(predicate), (r) => (r.length === 1 ? RA.get(r, 0) : O.none()))
);