bottender-compose/lib/logic.js

An utility library for bottender and higher-order handlers

"use strict";

const invariant = require('invariant');

function not(predicate) {
  return context => !predicate(context);
}

function and(predicates) {
  invariant(Array.isArray(predicates), `and: predicates must be an array. Recevied ${predicates}`);
  return context => predicates.every(predicate => predicate(context));
}

function or(predicates) {
  invariant(Array.isArray(predicates), `or: predicates must be an array. Recevied ${predicates}`);
  return context => predicates.some(predicate => predicate(context));
}

function alwaysTrue() {
  return () => true;
}

function alwaysFalse() {
  return () => false;
}

exports.not = not;
exports.and = and;
exports.or = or;
exports.alwaysTrue = alwaysTrue;
exports.alwaysFalse = alwaysFalse;