no-unused-vars produces frequent False Positives Involving Async/Await

Anytime you set a variable equal to the output of an async function and then do some other work before awaiting the returned promise, eslint falsely assumes that the variable is unused, when it actually is used.

Here’s the shortest example I could quickly come up with:

// esLint version 6.7.2
async function fnTest()
{
	return "Promise will resolve to this string.";
}
async function main()
{
	let usedVariable = fnTest(); // esLint thinks usedVariable is unused
	// Omitted: Do other things before awaiting usedVariable
	usedVariable = await usedVariable; // <------- Used!
}

This reminds me of a similar issue I reported 8 months ago: https://github.com/eslint/eslint/issues/11967

[mdjermanovic]

Thanks for clarifying this!

I’m closing this issue as a duplicate of #13181.

[Lonniebiz]

Ok, I’m starting to understand what you guys are telling me.

You all are saying that the real issue is that the wrong line is being reported as unused by eslint and that anytime a reassignment isn’t used, that too is “fair game” for no-unused-var, but it should be properly marked as “unused reassignment” (and the correct line should be reported instead of the one eslint is currently reporting). Yes, indeed, that is what has caused the confusion.

@anikethsaha : I finally understand what you were saying. I agree now; the real issue is #13181. Thanks for your patience.

Let this thread stand as a testament to the confusion #13181 can cause!