jscodeshift snippet - printing a whole MemberExpression

I’ve been writing codemods using jscodeshift. I find that while the main goal of codemods is to refactor code, I often have to print some output either for debugging or making sure I’m on the right path.

One of the things I had to do recently was to print a whole MemberExpression based on a module name I was looking for. For example, consider the following code snippet.

myUtils.doAction();
// ...
myUtils.subModule.doAction();
// ...
myUtils[selectedSubModule][selectedAction]();
// ...
myUtils[selectedSubModule][SOME_NAMESPACE.CONSTANT_NAME];

From the code above, I want to be able to print, in full, all the MemberExpressions related to myUtils. Below is the desired output.

myUtils.doAction
myUtils.subModule.doAction
myUtils[selectedSubModule][selectedAction]
myUtils[selectedSubModule][SOME_NAMESPACE.CONSTANT_NAME]

This turns out to be a very simple thing to do. We just have to do the following.

1. Locate a MemberExpression that has an Identifier named myUtils as the object.

2. If the MemberExpression from (1) is part of another MemberExpression, find the root MemberExpression.

   (For example, the myUtils.subModule, though a MemberExpression, is still the object in myUtils.subModule.doAction.)

3. Print the root MemberExpression using toSource().

We should end up with something like below.

// print-root-member-expressions.js
export default function printRootMemberExpressions(file, api) {
  const j = api.jscodeshift;

  const getRootMemberExpressionPath = p => {
    if (j.MemberExpression.check(p.parent.node)) {
      return p.parent;
    }

    return p;
  };

  const getRootMemberExpressionSource = p => {
    const rootMemberExpressionPath = getRootMemberExpressionPath(p);
    return j(rootMemberExpressionPath).toSource();
  };

  j(file.source)
    .find(j.MemberExpression, {
      object: {
        name: "myUtils"
      }
    })
    .forEach(path => {
      console.log(getRootMemberExpressionSource(path));
    });
}

See it in action on AST Explorer. Check the console log.