agson/lib/agson/traversals.js

Querying and manipulating JSON graphs

(function() {
  var Just, Nothing, Traversal, fromNullable, isArray, isObject, list, maybeMap, maybeMapValues, nothing, object, traversal, _ref, _ref1;

  _ref = require('data.maybe'), Just = _ref.Just, Nothing = _ref.Nothing, fromNullable = _ref.fromNullable;

  _ref1 = require('./util'), maybeMap = _ref1.maybeMap, maybeMapValues = _ref1.maybeMapValues, isArray = _ref1.isArray, isObject = _ref1.isObject;

  Traversal = require('./Traversal');

  traversal = Traversal.of;

  nothing = {
    modify: Nothing,
    get: Nothing
  };

  list = traversal("list", function(mta) {
    return {
      modify: function(f) {
        return mta.chain(function(ta) {
          if (!isArray(ta)) {
            return Nothing();
          } else {
            return Just(maybeMap(ta, function(a) {
              return f(fromNullable(a));
            }));
          }
        });
      },
      get: function() {
        return mta.chain(function(ta) {
          if (!isArray(ta)) {
            return Nothing();
          } else {
            return Just(ta);
          }
        });
      }
    };
  });

  object = traversal("object", function(mo) {
    return {
      modify: function(f) {
        return mo.map(function(object) {
          if (!isObject(object)) {
            return Nothing();
          } else {
            return maybeMapValues(object, function(value) {
              return f(fromNullable(value));
            });
          }
        });
      },
      get: function() {
        return mo.chain(function(object) {
          if (!isObject(object)) {
            return Nothing();
          } else {
            return Just(object);
          }
        });
      }
    };
  });

  module.exports = {
    list: list,
    object: object
  };

}).call(this);