Multiple get API in MEAN.IO (Express, Angular)

In traditional REST API, we should define our API like this:

• GET /api/things -> get all
• POST /api/things -> create
• GET /api/things/:id -> get one
• PUT /api/things/:id -> update
• DELETE /api/things/:id -> delete

How should i define another 'get one' endpoint for querying data by any other field other than id? For example:

• GET /api/things/:title -> get one by title (this sure does not work since the api isn't aware of URL parameter names)

• GET /api/things/title/:title ? this does not work for me at all..

• GET /api/things?title=whatever (this cannot be defined at all. When i write this in my index.js:

  router.get('?title=whatever', controller.getByTitle);

I get this:

SyntaxError: Invalid regular expression: /^?title=whatever\/?$/: Nothing to repeat
    at RegExp (native)

ID should be an unique identifier. Given one ID, you should return one resource at most. That's why an URI like GET /api/things/:id makes sense.

For other properties which may or may not be unique, you can have more than one result, so use the GET /api/things endpoint and pass query parameters : /api/things?title=mytitle.

app.get('/api/things', function (req, res) {
    console.log(req.query.title); //mytitle
    ThingModel.find({
       title: req.query.title    
    }, function (err, things) {
         res.send(things);
    });
});