Using fusspot for more than validation?

TLDR: Certain functions in node.js application could benefit from fusspot's parameter validation. This could be used as a sort of react-props for node.js which validates only when running the tests.

A lot of times a simple typo could silently sneak in and cause unexpected behaviour. In the example below, emphasise would remain falsy since foo gets the wrong parameter property.

const foo = ({ abc, xyz, tgif, emphasise }) => {
   if (emphasise) {
      return chalk.bold('I am emphasised');
   }
}

foo({ abc, xyz, tgif, emphasize }); // a simple American to British glitch

Also, if a fellow developer decides to change foo's parameter schema, she/he needs to dig into all the call sites of foo to fix it. These problems aren't anything new and can be carefully fixed with unit testing.

My proposal is that we use fusspot along with unit testing to write less test cases and catch bugs early on. A function could be wrapped around an assertion function (v.assertParams?) and the code would only validate when running tests i.e. NODE_ENV=test else it would simply be a passthrough (for performance reasons).

One of the drawbacks of this approach would be that we would need to write the parameters at two places and keep them in sync. Also, it is a non standard solution and might throw some people off.

Start by reviewing fusspot's existing assertion capabilities and the proposed v.assertParams-style wrapper. Clarify the API, how NODE_ENV=test should control validation, and how unit tests would demonstrate parameter mismatches and passthrough behavior; the issue mentions no files or existing tests to begin with.