@dillonkearns/elm-graphql/examples/src/subscription/node_modules/flow-static-land/lib/PSetter.js

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'use strict';

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.set = set;
exports.choice = choice;
exports.composeSetter = composeSetter;
exports.fromFunctor = fromFunctor;

var _HKT = require('./HKT');

var _Either = require('./Either');

var either = _interopRequireWildcard(_Either);

function _interopRequireWildcard(obj) { if (obj && obj.__esModule) { return obj; } else { var newObj = {}; if (obj != null) { for (var key in obj) { if (Object.prototype.hasOwnProperty.call(obj, key)) newObj[key] = obj[key]; } } newObj.default = obj; return newObj; } }

/*

 A [[PSetter]] is a generalisation of Functor map:
 - `map:    (A => B) => F[A] => F[B]`
 - `modify: (A => B) => S    => T`

*/

function set(setter, b, s) {
  return setter.modify(function () {
    return b;
  }, s);
}

/** join two PSetter with the same target */
function choice(setter1, setter2) {
  return {
    modify: function modify(f, s) {
      return either.either(function (s1) {
        return either.left(setter1.modify(f, s1));
      }, function (s2) {
        return either.right(setter2.modify(f, s2));
      }, s);
    }
  };
}

function composeSetter(abcd, stab) {
  return {
    modify: function modify(f, s) {
      return stab.modify(function (c) {
        return abcd.modify(f, c);
      }, s);
    }
  };
}

function fromFunctor(functor) {
  return {
    modify: function modify(f, s) {
      return functor.map(f, s);
    }
  };
}