import Sequence from "./Sequence";
export declare class IndexOfFirst {
    /**
     * Returns the zero-based index of the first element matching the given `predicate` or -1 if no element matches
     * the predicate.
     *
     * @param {(value: T) => boolean} predicate
     * @returns {number}
     */
    indexOfFirst<T>(this: Sequence<T>, predicate: (value: T) => boolean): number;
}