How to wrap an object into a function return this object using jscodeshift

Question

Let's say I have the following file

export default {
  foo: 'bar'
}

How can I transform this file using jscodeshift so it wraps the object into function like this:

export default () => ({
  foo: 'bar'
})

My main problem is how to use the api.jscodeshift.arrowFunctionExpression(), especially how to create the function body. Cause I think all I need to do, is to replace the ObjectExpression with a function that has the ObjectExpression as its body.

Answer 1

Found out by myself. arrowFunctionExpression take a list params and then a blockStatement. This will generate the function:

const fn = j.arrowFunctionExpression(
    [{ type: "Identifier", name: "theme" }],
    j.blockStatement([j.returnStatement(stylesObject)])
  );

Then create a new exportDefaultDeclaration and pass the function to it.

const e = j.exportDefaultDeclaration(fn)

  return j(e).toSource(); 

Answer 2

Another option is to use j.template.expression which is a tagged template that lets you interpolate JavaScript with existing nodes:

Complete example:

  return j(file.source)
    .find(j.ExportDefaultDeclaration)
    .find(j.ObjectExpression)
    .replaceWith(
      path => j.template.expression`theme => ${path.node}`
    )
    .toSource();