title: Why would I get a "Promise is not defined." error on Node v5.7.0
body: <p>Im using <a href="https://www.npmjs.com/package/autoprefixer" rel="noreferrer">autoprefixer</a> with <a href="https://github.com/postcss/postcss" rel="noreferrer">postcss</a> and after moving to a new linux server something must be wrong but I cant figure out what this one could be. I'm getting the error:</p>
  
  <pre><code>/home/ec2-user/Enviziion/Muveoo/Server/node_modules/postcss/lib/lazy-result.js:157
          this.processing = new Promise(function (resolve, reject) {
                                ^
  ReferenceError: Promise is not defined
  </code></pre>
  
  <p>Which is triggered by:</p>
  
  <pre><code>var autoprefixer = require('autoprefixer');
  var postCSS = require('postcss');
  
  function prefix(css, res, type, fullPath) {
      postCSS([autoprefixer]).process(css).then(function(result) {
          var css = result.css;
          var length = css.length;
          res.writeHead(200, {
              'Content-Length' : length,
              'Content-Type' : type
          });
          res.write(css);
          res.end();
      });
  }
  </code></pre>
  
  <p>I researched this problem but all of the occurrences of the issue seem to be for extremely early versions of node.js, for example:</p>
  
  <ul>
  <li><p><a href="https://stackoverflow.com/questions/21564993/native-support-for-promises-in-node-js">Native Support for Promises in Node.js</a></p></li>
  <li><p><a href="https://github.com/postcss/postcss-nested/issues/30" rel="noreferrer">https://github.com/postcss/postcss-nested/issues/30</a></p></li>
  </ul>
  
  <p>And the solution always seems to be "Update Node".</p>
  
  <p>But mine seems to be up to date:</p>
  
  <pre><code>[ec2-user@ip-172-31-22-79 Server]$ node -v
  v5.7.0
  </code></pre>
  
  <p>What might my issue be here?</p>