How to find a node without parent with jscodeshift?

Question

I want to find call expressions that doesn't have any parent in this script:

1 + 1

function parent() {
    2 + 2
}

3 + 3

Here I want to get 1 + 1 and 3 + 3 nodes but not 2 + 2.

What I'd like to achieve would be something like:

j(file.source).find(j.ExpressionStatement, {
    parent: null 
});

So is there a filter that allow to find if an expression has a parent ?

Here is a real use case.

Answer 1

Using Indentation (unsafe)

The loc attribute of an AST node has an indentation attribute. If the indentation is 0 when can assume that is a top level expression:

j(file.source).find(j.ExpressionStatement, {
    loc: {indent: 0} 
});

This is really not robust since it depends on indentation.

Chaining with a second filter

Since I couldn't find a safe way to filter over the attributes. We can also use jscodeshift's .filter() to get the parent node. If it is the program, then we're sure to be top-level:

j(file.source).find(j.ExpressionStatement)
              .filter(path => j.Program.check(path.parent.value));