How can ArrayExpression have null elements?

[tjenkinson]

It looks like that an element can be null in ArrayExpression

interface ArrayExpression <: Expression {
    type: "ArrayExpression";
    elements: [ Expression | null ];
}

How is this possible? What does null mean here?

Thanks

[mysticatea]

It's a sparse array. For example:

let array = [,,,]

[tjenkinson]

Thanks!

I opened a PR to add this: #207