Cryptic SyntaxError when passing only one argument to lookup

[mz8i]

Running the following code:

const a = aq.from([
    {A: 'a1', B: 'b1'},
    {A: 'a2', B: 'b2'}
])

const b = aq.from([
    {B: 'b1', C: 'c1'},
    {B: 'b2', C: 'c2'}
])

const c = a.lookup(b);

most intuitively, I would have expected this to infer the natural default for the values argument (which would be all columns apart from the one that is specified/inferred as the on argument) and yield a result equivalent to:

aq.from([
    {A: 'a1', B: 'b1', C: 'c1'},
    {A: 'a2', B: 'b2', C: 'c2'}
])

Instead, a SyntaxError is raised, presumably because the library internals generate invalid syntax due to an empty list of expressions passed in.

Please consider:

• allowing using lookup with only one argument, or
• improving the docs to specify that at least one expression is required (especially as the ...values rest argument comes after on which in the TypeScript typings is marked as optional, so it's easy to assume that everything apart from other is optional)

[jheer]

Thanks for the issue! I've added changes to make lookup keys and values optional in #380.

[mz8i]

Amazing, thank you!