Codemod: AMD in CommonJS style -> CommonJS

almost-amd-to-commonjs.js

/**
 * Run this with jscodeshift
 * Live demo: https://astexplorer.net/#/gist/3aec6fa8858f3ec0e0a82ab5ec4ad32d/latest
 *
 * Converts:
 *     define(function (require) {
 *       var React = require('react');
 *       const props = { foo: 'bar' };
 *       return React.createClass(props);
 *     });
 *
 * to:
 *     module.exports = function () {
 *       var React = require('react');
 *       const props = { foo: 'bar' };
 *       return React.createClass(props);
 *     }();
 */

"use strict";

module.exports = function(file, api) {
  const j = api.jscodeshift;
  return j(file.source)
    .find(j.ExpressionStatement)
    .filter(
      path =>
        path.parentPath.node.type === "Program" &&
        path.node.expression.type === "CallExpression" &&
        path.node.expression.callee.type === "Identifier" &&
        path.node.expression.callee.name === "define" &&
        path.node.expression.arguments.length === 1 &&
        ["FunctionExpression", "ArrowFunctionExpression"].indexOf(
          path.node.expression.arguments[0].type
        ) >= 0 &&
        path.node.expression.arguments[0].params.length === 1 &&
        path.node.expression.arguments[0].params[0].type === "Identifier" &&
        path.node.expression.arguments[0].params[0].name === "require"
    )
    .replaceWith(path => {
      var fn = path.node.expression.arguments[0];
      fn.params = [];
      var returnValue = j.expressionStatement(j.assignmentExpression(
        "=",
        j.memberExpression(
          j.identifier("module"),
          j.identifier("exports")
        ),
        j.callExpression(fn, [])
      ));
      returnValue.comments = path.node.comments;
      return returnValue;
    })
    .toSource();
};