Description

When a function accepts a single or multiple things. Though [foo].flat() is shorter and nicer, but it's not very clear to me.

I prefer Array.isArray(foo) ? foo : [foo]. If the array need to be cloned Array.isArray(foo) ? [...foo] : [foo].

But if the variable name is something like nameOrNames, [nameOrNames].flat() looks clear to me, maybe we can add an exception.

Fail

items = [items].flat();

Pass

items = Array.isArray(items) ? items : [items];

items = Array.isArray(items) ? [...items] : [items];

items = [...(Array.isArray(items) ? items : [items])];

const names = [nameOrNames].flat();