Safe cloning user object for further serialization

[chrisbujok]

Hello,

I tried to use this module with my feathers app and feathers-sequelize Users service, but functions sanitizeUserForClient and sanitizeUserForNotifier cause error:

TypeError: Converting circular structure to JSON
    at Object.stringify (native)
    at stringify (/***/node_modules/express/lib/response.js:1064:12)
    at ServerResponse.json (/***/node_modules/express/lib/response.js:243:14)
    at Object.applicationJson [as application/json] (/***/node_modules/feathers-rest/lib/index.js:27:11)
    at ServerResponse.res.format (/***/node_modules/express/lib/response.js:628:13)
    at formatter (/***/node_modules/feathers-rest/lib/index.js:25:7)
    at Layer.handle [as handle_request] (/***/node_modules/express/lib/router/layer.js:95:5)
    at next (/***/node_modules/express/lib/router/route.js:131:13)
    at Object.callback (/***/node_modules/feathers-rest/lib/wrappers.js:87:14)
    at callbackWrapper (/***/node_modules/rubberduck/lib/rubberduck.js:50:20)
    at /***/node_modules/feathers/lib/mixins/promise.js:35:14

I think this is because Object.assign() does not copy values like custom toJSON method, which is used e.g. in Sequelize model objects and is necessary for proper object serialization.

I came up with idea of checking for existence of custom toJSON method in user object and then using it's result as a source for new user object. It happens only when JSON.stringify() throws error, so in my opinion - only when necessary.

The caveat is that after object sanitization, sequelize methods inside model object will not be accessible, but this is the same situation as current.

Please let me know what do you think.

[eddyystop]

Thanks for the catch.
I somehow missed this PR for 3 days. Sorry.

MongoDB has a similar issue. It uses a .toObject function instead of .toJSON.
Perhaps cloneObject is more descriptive name that cloneUserObject.

Would you mind making these 2 changes to the PR?

[chrisbujok]

Sorry, I just found some time to fix this.
I've added support for toObject but toJSON has precedence over it.

[eddyystop]

+1 Thanks

[eddyystop]

Pushed with 0.1.6