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

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'use strict';

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.modify = modify;
exports.choice = choice;
exports.asOptional = asOptional;
exports.composeLens = composeLens;

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

var either = _interopRequireWildcard(_Either);

var _Getter = require('./Getter');

var getter = _interopRequireWildcard(_Getter);

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 Lens is an optic used to zoom inside a Product, e.g. case class, Tuple, HList or even Map.

  Lenses have two type parameters generally called S and A: Lens[S, A] where S represents the Product and A an element inside of S.

*/

function modify(lens, f, s) {
  return lens.set(f(lens.get(s)), s);
}

/** join two PLens with the same target */

function choice(lens1, lens2) {
  return {
    get: getter.choice(lens1, lens2).get,
    set: function set(b, s) {
      return either.bimap(function (s1) {
        return lens1.set(b, s1);
      }, function (s2) {
        return lens2.set(b, s2);
      }, s);
    }
  };
}

function asOptional(lens) {
  return {
    getOrModify: function getOrModify(s) {
      return either.right(lens.get(s));
    },

    set: lens.set
  };
}

function composeLens(abcd, stab) {
  return {
    get: function get(s) {
      return abcd.get(stab.get(s));
    },
    set: function set(d, s) {
      return modify(stab, function (a) {
        return abcd.set(d, a);
      }, s);
    }
  };
}