compose

compose :: [ Function ] → a → Boolean

It's the very backbone of Deep Waters, it takes a list of validators $[validators]$ (functions that accept a value and return a boolean) and returns a new function that takes a value $v$ and evaluates whether $v$ is valid for all the validators in $[validators]$.

isEmail.js

import compose from './compose';
import isString from './isString';
import matchesPattern from './matchesPattern';

const isEmail = compose(
  isString,
  matchesPattern(/^\w+([.-]?\w+)*@\w+([.-]?\w+)*(\.\w{2,3})+$/),
);

export default isEmail;

Please note, compose removes all the duplicate validators

Related validators

whenornot