如何将带有“ $”字段的JSON对象插入流星集合？

Question

I am retrieving data about books from the Amazon API and storing it as a JSON object. I then want to insert this data into a Meteor collection. However, some fields in the JSON data begin with the "$" character, which leads to this error:

MongoError: The dollar ($) prefixed field '$' in 'result.results.0.ItemAttributes.0.ManufacturerMaximumAge.0.$' is not valid for storage.

I would like help to insert data into the collection given that the data contains "$" signs. If that is not possible,is there a way to remove all occurrences of "$" in the JSON data and THEN store it into the Meteor collection? Here is my code, given a Book title and author, that searches the Amazon API and returns information about the first 10 results: (SearchResult is the reference to the collection)

    Meteor.methods({
    itemSearch(appUUID,title, author) {
        var result = {};
        result.search = {
            appUUID: appUUID,
            title: title,
            author: author
        }
        client.itemSearch({
            title: title,
            author: author,
            searchIndex: 'Books',           
            responseGroup: 'ItemAttributes, Images'
        }).then(function(results){
           result.results = results;
           var upsertResult = SearchResult.upsert( {
                appUUID: appUUID,
                title: title,
                author: author,
            },
            {
                $set: {result: result}
            }
           );
        }).catch(function(err){
                    SearchResult.upsert({
                    appUUID: appUUID,
                    title: title,
                    author: author,
                },    
                { 
                    $set: {result: result }
                }
            );
        });

    }
});

This is the JSON data, and the dollar sign before "Units" is what is causing the issue.

"Width": [
       {
        "_": "810",
        "$": {
             "Units": "hundredths-inches"
             }
       }
 ]

Answer 1

Simple answer is, no, you cannot use the $ in fields in MongoDB (from the docs ):

The field names cannot start with the dollar sign ($) character.

There are many possible solutions to change your data into a format that MongoDB can accept, but to give you the simplest solution I can think of, you can just map the keys of the object. For example, with lodash's mapKeys function :

data = _.mapKeys(data, (value, key) => {
  if(key === '$') {
    return 'some_custom_key'
  } else {
    return key
  }
})

This would change all your $ into some_custom_key . As long as you have hooks (such as Mongoose's pre save middleware and post read middleware, docs ) that can convert this for you under-the-hood, it should be a somewhat workable solution.

I don't know if it's possible, but a better solution would be to get Amazon API to give you the data without $ , but I can't speculate about that since I'm unfamiliar with that API.