Converts commonJS requires to es6 imports

requiresToImports.js

// converts commonJS requires to es6 imports
//   var foo = require('foo');
// ->
//   import foo from 'foo';
//
// jscodeshift -t requiresToImports.js src/**/*.js*
'use strict';

module.exports = function(fileInfo, api) {
  var j = api.jscodeshift;
  var root = j(fileInfo.source);

  root
    .find(j.VariableDeclaration, {
      declarations: [{
        type: 'VariableDeclarator',
        init: {
          type: 'CallExpression',
          callee: {
            type: 'Identifier',
            name: 'require',
          },
        },
      }],
    })
    .filter(isTopLevel)
    .forEach(function(path) {
      const dec = path.value.declarations[0];
      const id = dec.id;
      const source = dec.init.arguments[0];
      const comments = path.value.comments;
      const loc = path.value.loc;

      path.replace(
        j.importDeclaration(
          [{
            type: 'ImportDefaultSpecifier',
            id
          }],
          source
        )
      );
      path.value.loc = loc;
      path.value.comments = comments;
    });

  root
    .find(j.VariableDeclaration, {
      declarations: [{
        type: 'VariableDeclarator',
        init: {
          type: 'MemberExpression',
          object: {
            type: 'CallExpression',
            callee: {
              type: 'Identifier',
              name: 'require'
            },
          },
        },
      }],
    })
    .filter(isTopLevel)
    .forEach(function(path) {
      const dec = path.value.declarations[0];
      const name = dec.id;
      const source = dec.init.object.arguments[0];
      const id = dec.init.property;
      const comments = path.value.comments;
      const loc = path.value.loc;

      let spec = {
        type: 'ImportSpecifier',
        id,
      }
      if (name.name !== id.name) {
        spec['name'] = name;
      }

      path.replace(j.importDeclaration([spec], source));
      path.value.loc = loc;
      path.value.comments = comments;
    });

  return root.toSource();
};

function isTopLevel(path) {
  return !path.parentPath.parentPath.parentPath.parentPath;
}

FYI for others, this doesn't catch require calls that don't assign to a variable, i.e. require('foo') instead of var foo = require('foo').