title: babel-node es6 "Modules aren't supported in the REPL"
body: <p><code>babel-preset-es2015</code> is installed, and is OK with es6 feature just like below <code>let a = 2;</code>.<br>
  But can not work with es6 modules feature <code>import fs from 'fs'</code> as following:  </p>
  
  <pre><code>$ babel-node --presets es2015
  &gt; let a = 2;
  'use strict'
  &gt; a
  2
  &gt; import fs from 'fs';
  SyntaxError: repl: Modules aren't supported in the REPL
  import fs from 'fs';  
      at File.buildCodeFrameError (/usr/lib/node_modules/babel-cli/node_modules/babel-core/lib/transformation/file/index.js:407:15)
      at NodePath.buildCodeFrameError (/usr/lib/node_modules/babel-cli/node_modules/babel-traverse/lib/path/index.js:149:26)
      at PluginPass.ModuleDeclaration (/usr/lib/node_modules/babel-cli/lib/_babel-node.js:78:20)
      at newFn (/usr/lib/node_modules/babel-cli/node_modules/babel-traverse/lib/visitors.js:262:19)
      at NodePath._call (/usr/lib/node_modules/babel-cli/node_modules/babel-traverse/lib/path/context.js:63:18)
      at NodePath.call (/usr/lib/node_modules/babel-cli/node_modules/babel-traverse/lib/path/context.js:47:17)
      at NodePath.visit (/usr/lib/node_modules/babel-cli/node_modules/babel-traverse/lib/path/context.js:93:12)
      at TraversalContext.visitQueue (/usr/lib/node_modules/babel-cli/node_modules/babel-traverse/lib/context.js:152:16)
      at TraversalContext.visitMultiple (/usr/lib/node_modules/babel-cli/node_modules/babel-traverse/lib/context.js:110:17)
      at TraversalContext.visit (/usr/lib/node_modules/babel-cli/node_modules/babel-traverse/lib/context.js:182:19)
  </code></pre>
  
  <p>So what's wrong?<br>
  Thanks!</p>