match-api.js

const match = (field, delegate) => {
  return (data = []) => {
    return data.filter(entry => delegate(entry[field]));
  }
};

const isMale = (value) => value === 'male';
const isFemale = (value) => value === 'female';

const getMales = match('gender', isMale);
const getFemales = match('gender', isFemale);

const males = getMales(data);
const females = getFemales(data);

console.log(`we've got ${females} femalse and ${males} males`);