change .default-less require calls for certain modules to require().default

require-default-codeshift.js

/**
 * add .default to requires for 'stores/index' that don't already have them.
 *
 * this comes up because babel6 Does The Right Thing with es6 exports and
 * commonjs requires now need to play by the rules of the es6 exported modules
 * and specify the default argument. see more:
 * https://medium.com/@kentcdodds/misunderstanding-es6-modules-upgrading-babel-tears-and-a-solution-ad2d5ab93ce0#.tjlvbfd4x
 * 
 */
export default function transformer(file, api) {
  const j = api.jscodeshift;
  const {expression, statement, statements} = j.template;

  return j(file.source)
    .find(j.VariableDeclarator, {init: { type: 'CallExpression', callee: 
                             {name: 'require'}, 
                             arguments: [{value: 'stores/index'}]}})
    .replaceWith(
      p => j.variableDeclarator(
        p.node.id,
        j.memberExpression(
        	p.node.init,
        	j.identifier('default')
      ))
    )
    .toSource();
};

the effect is going from

var newStore = require('stores/index').default;
var oldStore = require('stores/index');
var somethingElse = require('storeso/index');

to

var newStore = require('stores/index').default;
var oldStore = require('stores/index').default;
var somethingElse = require('storeso/index');