'use strict';

Object.defineProperty(exports, Symbol.toStringTag, { value: 'Module' });

function differenceBy(firstArr, secondArr, mapper) {
    const mappedSecondSet = new Set(secondArr.map(item => mapper(item)));
    return firstArr.filter(item => {
        return !mappedSecondSet.has(mapper(item));
    });
}

exports.differenceBy = differenceBy;