FPWay.js

var users = [
   {
      role: 'admin',
      email: 'fakeadmin1@email.com'
   },
   {
      role: 'user',
      email: 'fake2@email.com'
   },
   {
      role: 'admin',
      email: 'fakeadmin2@email.com'
   },
];
function compose(f,g) {
    return function (x) {
        return f(g(x));
    };
}
function property(p) {
    return function (x) {
        return x[p];
    };
}
function propertyp(v) {
    return function (p) {
        return function (o) {
            return property(p)(o) == v;
        };
    };
}
function map(fn) {
    return function (list) {
        return list.map(fn);
    };
}
function filter(fn) {
    return function(list) {
        return list.filter(fn);
    }
}
function onlyAdmins() {
    return filter(propertyp('admin')('role'));
}
function onlyEmails() {
      return map(property('email'));
}
var getAdminEmails = compose(
    onlyEmails(),
    onlyAdmins());
var admin_emails = getAdminEmails(users);