https://github.com/sindresorhus/eslint-plugin-unicorn/blob/2b469bee475a8f3f2767f4669864acdd89654017/test/no-useless-spread.mjs#L259
[!NOTE]
The concat() method preserves empty slots if any of the source arrays is sparse.
via MDN
const foo = new Array(5);
const bar = new Array(5);
const cat = [...foo.concat(bar)];
// now we got a new array with undefined x 10
// but foo.concat(bar) is empty x 10.
// It's not what we want.
