title: Nodejs v8.6.0 getting warning: [DEP0013] DeprecationWarning: Calling an asynchronous function without callback is deprecated
body: <p>I am learning node, and in the program below I am getting the warning stating:</p>
  
  <blockquote>
    <p>"(node:93236) [DEP0013] DeprecationWarning: Calling an asynchronous
    function without callback is
    deprecated."(<a href="https://nodejs.org/api/deprecations.html#deprecations_dep0013_fs_asynchronous_function_without_callback" rel="nofollow noreferrer">https://nodejs.org/api/deprecations.html#deprecations_dep0013_fs_asynchronous_function_without_callback</a>)</p>
  </blockquote>
  
  <p>script:</p>
  
  <pre><code>var fs = require('fs');
  
  
  fs.open('test.txt', 'r', function (err, handle) {
      if (err == null) {
          var f = handle;
          var b = new Buffer(100000);
  
          fs.read(f, b, 0, 100000, null, function (err, bytes_read) {
              if (err == null) {
                  console.log(b.toString("utf8", 0, bytes_read));
              } else {
                  console.log("Oh Noes! fail on read: " + err.code + " " + err.message);
              }
              fs.close(f);
          });
      } else {
          console.log("Oh noes! fail an open: " + err.code + " " + err.message);
      }
  });
  </code></pre>
  
  <p>How should I proceed in order to find how a callback function should be properly included in these functions fs.open(...) and fs.read(...)?
  Thanks!</p>