Mithril serialization patch

mithril-patch.js

// Recursively traverses any object or array of objects and converts object
// keys from under_score to camelCase.
function camelize(object) { /* ... */ }

// Recursively traverses any object or array of objects and converts object
// keys from camelCase to under_score.
function underscore(object) { /* ... */ }

// Accepts Mithril's `m` object and Decorates the `m.request` function to
// deserialize using the `camelize` function and to serialize using the
// `underscore` function, unless a `deserialize` or `serialize` option
// respectively is already provided.
//
// The amount of specialization required to decorate Mithril like this makes
// me question if this is the right thing to do.
function patchMithril(m) {
  const originalRequest = m.request;

  m.request = function(opts) {
    const originalConfig = opts.config;
    const hasNewDeserialize = !opts.deserialize;
    const hasNewSerialize = !opts.serialize;

    if (hasNewDeserialize) {
      opts.deserialize = function(data) {
        return camelize(JSON.parse(data));
      };

      // This specialization is getting ridiculous!
      opts.extract = function(xhr) {
        return xhr.responseText || null;
      };
    }

    if (hasNewSerialize) {
      opts.serialize = function(data) {
        return JSON.stringify(underscore(data));
      };
    }

    opts.config = function(xhr) {
      // These XHR headers are applied by Mithril if and only if `deserialize`
      // is set to the default `JSON.parse` and `serialize` is set to the
      // default `JSON.stringify`. Because we are replacing the default
      // serializer and deserializer, we must reimplement this feature.

      if (hasNewDeserialize) {
        xhr.setRequestHeader('Accept', 'application/json, text/*');
      }

      if (hasNewSerialize && opts.data && opts.method !== 'GET') {
        xhr.setRequestHeader('Content-Type', 'application/json; charset=utf-8');
      }

      if (originalConfig) {
        originalConfig(xhr, opts);
      }
    };

    return originalRequest.call(m, opts);
  };
}