Rule suggestion: Don't reassign function parameters

Reusing function parameters feels often like a code smell for me. If you consider something like the following example it could even cost you some debugging time (especially if you have long legacy functions):

function foo (bar) {
    bar = 13;
    // now we accidentally overwrote the function parameter which is most likely not good
}

I suggest the implementation of a rule that is similar to no-ex-assign but for functions instead of try-catch-blocks and is turned off by default.

What do you think about it?

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[idchlife]

@xjamundx oh, I see. I did not know about () around {} when returning object in short function.

That’s actually just flowtype, not typescript.

[xjamundx]

@idchlife this is valid ES6 [1,2].map(c => ({a: 1})) not sure about TypeScript?