title: How do I call a Vue method into a plain javascript function?
body: <p>Vue app code:</p>
  
  <pre><code>var app = new Vue({
      el: "#APP",
      data: {some data},
      methods: {
              some_method: function() {
                     ......
              }
  });
  
  some_js_func = function() {
         "How do I call 'some_method' to here"
  };
  some_js_func();
  </code></pre>
  
  <p>I tried by calling <code>app.some_method()</code>, but it's  not working.</p>