Rails is kinda like that friend you have who's really into foreign films. It knows what it likes and is very picky about what it will accept. Especially with params. If you build your param hashes out correctly in rails, life is swell. Submitting forms is a breeze. You can instantiate a new object, feed it params, and let rails sort out the rest. But if you don't build out the data for params correctly, submitting forms and updating objects in you db is a royal pain.
Building the correct data structure for params is easy enough with erb or some other rails templating language that builds out html. But what if you are using one of these modern front end frameworks to build you app is javascript? Gasp! Don't tell DHH!
Let's look at a pattern that we have come up with here at Littlelines to build out params hashes that play nice with rails using the Vue framework's computed property functionality.