partialRight in Lodash seems to do nothing

Question

(I couldn't find an open Lodash Slack channel, that's why I'm posting here.)

Could you please tell me why the partialRight in this fiddle seems to do nothing? The correctRenameKeys function correctly renames the key in the supplied object, but the wrongRenameKeys function - which should do exactly the same - doesn't.

Please open the JavaScript console in your browser to see logs when running the fiddle. I tested it in Chrome.

    const renameKeysOfOneObject = (object, keyMappings) => {
      return _.reduce(object, function(result, value, key) {
        key = keyMappings[key] || key;
        result[key] = value;
        return result;
      }, {});
    };

    const correctRenameKeys = (objects, keyMappings) => {
        const keysRenamer = object => renameKeysOfOneObject(object, keyMappings);
        return _.map(objects, keysRenamer);
    };

    const wrongRenameKeys = (objects, keyMappings) => {
        const keysRenamer = _.partialRight(renameKeysOfOneObject, keyMappings);
        return _.map(objects, keysRenamer);
    };

    const object = {keyToBeRenamed: 'someValue'};
    const objects = [object];
    const keyMapping = {keyToBeRenamed: 'newKeyName'};

    const correctlyRenamed = correctRenameKeys(objects, keyMapping);
    const wronglyRenamed = wrongRenameKeys(objects, keyMapping);

    console.assert(_.isEqual(correctlyRenamed, wronglyRenamed), 
                   "The two objects should be equal. " + 
                   "The 'keyToBeRenamed' key should have been renamed to 'newKeyName'.");
    console.log(correctlyRenamed);
    console.log(wronglyRenamed);

partialRight in Lodash seems to do nothing

1 Answers