[runarberg]

> In general the spread operator should only be used for forwarding arguments not for array operations.

Not quite. You should also use the spread operator when you are spreading an iterable into an array:

    const unique = [...new Set(arr)];

[masklinn]

Seems like a needlessly unreadable alternative to Array.from unless you're combining multiple iterables or values an iterables e.g.

    const unique = [...a, ...b];

You might expect that concat would work, but it doesn't handle arbitrary iterables:

    > [].concat([1][Symbol.iterator](), [2][Symbol.iterator]())
    [Array Iterator, Array Iterator]
    > [...[1][Symbol.iterator](), ...[2][Symbol.iterator]()]
    [1, 2]