Fix for certain child modules not getting cleared

[sondregj]

When clearing a module, certain child modules seem to be skipped.

This seems to be because the require.cache[idx].parent.children array is mutated with an Array.splice-call inside the next recursive call to clear(), skipping certain indices in the outer for-loop over children.

while (i--) {
	if (require.cache[filePath].parent.children[i].id === filePath) {
		// seems to mutate iterator in snippet below, one level of recursion above
		require.cache[filePath].parent.children.splice(i, 1);
	}
}

for (const {id} of children) { // certain indices of `children` do not get cleared?
	clear(id);
}

Making a new array fixes the issue.

Looking at the test clearModule() recursively, before using clearModule, delete require.cache[require.resolve(id)]; is executed. I am not sure if this is part of the expected usage of the function, but the test fails if it is removed. If you swap the order of the imports in fixture-with-dependency.js, the test succeeds.

I chose to split the commits into three so that you may first review the failing test, and then consider how the fix should look.

[sindresorhus]

Thanks for fixing 👍