Alternate updateIn() for ImmutableJS

updateIn.js

/**
 * Convenience function for deep updates including searches in the path
 */
export default function updateIn(immutableType, pathArray, updater) {
  // pathArray can contain matcher functions
  let failed = false;
  let parsedPath = [];
  
  pathArray.every( (pathEl, idx) => {    
    if (typeof pathEl !== 'function' && typeof pathEl !== 'object') {
      parsedPath.push(pathEl);
      return true;
    }
    
    let items = immutableType.getIn(parsedPath);
    let fn;

    // if it's an object, then our match function requires all keyed entries match
    if (typeof pathEl === 'object') {
      fn = function (list) {
        let keys = Object.keys(pathEl);
        return list.findIndex( item => {    
          for (let key of keys) {
            if (item.get(key) !== pathEl[key]) return false;
          }
          return true;
        });
      }
    } else {
      fn = function (list) {
        return list.findIndex( pathEl );
      };
    }
    
    let index = fn(items);
    
    // TODO: this isn't robust enough
    if (index === -1) {
      failed = true;
      return false;
    }
    
    parsedPath.push( index );
    return true;
  });
  
  if (failed) {
    // TODO: is this how we want to operate?
    return undefined;
  }
  
  return immutableType.updateIn(parsedPath, function (item) {    
    return updater(item, immutableType);
  });
}

updateInExample.js

import Immutable from 'immutable';
import updateIn from './updateIn';

/****************************************************************************************
 *
 * Example as per https://gist.github.com/kastermester/8c40b35843a38ea7ef5d
 *
 ****************************************************************************************/

let state = Immutable.fromJS({
  product_preview: {
    product_type: '',
    media_items: [
      {id: 0, url: 'my_url'}, 
      {id: 1, url: 'my_url'},
      {id: 2, url: 'my_url'}
    ],
  },
});

/*
// Lastly, using `updateIn`
var newState = state.updateIn(['product_preview', 'media_items'], function(list){
	var idx = list.findIndex(function(item){
		return item.get('id') === 1;
	});
	return list.setIn([idx, 'url'], 'my_new_url');
});
*/

var newState = updateIn(state, ['product_preview', 'media_items', {id:1}], function (item, list) {
  return item.set('url', 'new_url');
});

// or alternatively:

var newState2 = updateIn(state, ['product_preview', 'media_items', item => item.get('id') === 1], function (item, list) {
  return item.set('url', 'new_url');
});