Lis properties of CanvasRenderingContext2D

嗨，我正在尝试列出CanvasRenderingContext2D对象的所有方法和属性。我在列出方法方面取得了成功，但是当我尝试列出属性时，我得到了奇怪的结果。我得到的只是重复多次相同属性的 ana 数组。有人可以帮助我吗？

var canvas = document.querySelector('#canvas');
var ctx = canvas.getContext('2d');
 var methods = [];
        for (var m in ctx) {
            if (typeof ctx[m] == "function") {
                methods.push(m);
                methods.join(',');
            }
        }
        var methodsContainer = document.querySelector('#methods');
        for(var i = 0; i < methods.length; i++) {
            var opt = methods[i];
            var el = document.createElement("option");
            el.textContent = opt;
            el.value = opt;
            methodsContainer.appendChild(el);
        }
  var properties = [];
        for (var key in ctx) {
            if (Object.getOwnPropertyNames(ctx)) {
                properties.push(m);
                properties.join(',');
            }
        }
        var propertiesContainer = document.querySelector('#properties');
        for(var i = 0; i < methods.length; i++) {
            var opt = properties[i];
            var el = document.createElement("option");
            el.textContent = opt;
            el.value = opt;
            propertiesContainer.appendChild(el);
        }

  <canvas id="canvas"></canvas> 
  
  <h5>Methods</h5>
  <select id="methods">
  </select>
  <br/>
  <h5>Properties</h5>
  <select id="properties">
  </select>