SyntaxError when using core-js polyfills

[rafaelfbs]

When bundling code which uses getOwnPropertyNames, getPrototypeOf, etc, this error happens:

SyntaxError: 'import' and 'export' may only appear at the top level (2:0) in /home/****/****/node_modules/core-js/library/modules/$.is-object.js
    at Parser.pp$4.raise (/home/****/****/node_modules/gulp-rollup/node_modules/rollup/dist/rollup.js:4271:13)
    at Parser.pp$1.parseStatement (/home/****/****/node_modules/gulp-rollup/node_modules/rollup/dist/rollup.js:2836:29)

My code:

function propertiesOf(klass) {
  let proto = klass;
  let props = [];
  let keys;

  do {
    proto = Object.getPrototypeOf(proto);
    keys  = Reflect.ownKeys(proto);

    props = props.concat(
      keys.filter(key => props.indexOf(key) < 0)
    );
  }
  while (typeof proto === 'function');

  return props;
}

The transformed code of "$.is-object.js" after commonjs plugin:

var $_isObject = __commonjs(function (module) {
import _typeof from 'babel-runtime/helpers/typeof';
module.exports = function (it) {
  return (typeof it === 'undefined' ? 'undefined' : _typeof(it)) === 'object' ? it !== null : typeof it === 'function';
};
});

export default ($_isObject && typeof $_isObject === 'object' && 'default' in $_isObject ? $_isObject['default'] : $_isObject);

[darlanalves]

This is quite common with other libraries or app codes as well.

The problem is due to import clauses inserted in the same place of require() calls. All the import declarations should be moved to the top of the file to fix this.

A similar code that will probably break too:

var fs = require('fs');

function readFile(file) {
  // this will be turned into a import directive
  var path = require('path');

  var fullPath = path.join(__dirname, file);
  return fs.createReadStream(fullPath);
}

// ...

[Rich-Harris]

Sorry for leaving this open such a long time. This is fixed in recent versions of the plugin – closing