"else path not taken" but it was

[ki9us]

I have a function with an options object as an argument. Each key in the object takes a boolean, defaulting to true. At first, I wrote it like this:

myFunction = function( options={
  // Defaults
  opt1: true,
  opt2: true,
  // ...
} ){
  if (options.opt1) {
    // Do stuff
  }
  if (options.opt2) {
    // Do other stuff
  }
  // ...
}

However, I noticed that if I called it like this:

myFunction({opt2:false})

...the options object was incomplete, leaving options.opt1 as undefined (and therefore falsy). So I changed my code to explicitly check if the option had been set to false. That way, the if statement would include these undefined options:

myFunction = function( options={
  opt1: true,
  // ...
} ){
  if (options.opt1!==false) { // Problem solved
    // Do stuff
  }
}

Now this might not be the best way to do things... and I am taking suggestions, but that's beside the point.

I ran some tests for possibilities where each option could be false:

// A test
myFunction({opt1:false})
// Another test
myFunction({opt2:false})

So opt2 defaults to true, erm, undefined in the first test and opt1 is true in the second. You see, I have followed both implicit else branches. The tests are running correctly, so I know the if-statements are working as intended.

Each if-statement is throwing the "else path not taken" error. Is it a bug?

Feel free to clone the entire repo to reproduce this.