List Down All Prototype Properties of an Javascript Object

Question

Is there any other way to look up for the prototype properties of an javascript object. Lets say I have like this.

function proton() {
    this.property1 = u         


        

Answer 1

Not a prototype method, but you can use Object.getPrototypeOf to traverse the prototype chain and then get the own property names of each of those objects.

function logAllProperties(obj) {
     if (obj == null) return; // recursive approach
     console.log(Object.getOwnPropertyNames(obj));
     logAllProperties(Object.getPrototypeOf(obj));
}
logAllProperties(my_object);

Using this, you can also write a function that returns you an array of all the property names:

function props(obj) {
    var p = [];
    for (; obj != null; obj = Object.getPrototypeOf(obj)) {
        var op = Object.getOwnPropertyNames(obj);
        for (var i=0; i<op.length; i++)
            if (p.indexOf(op[i]) == -1)
                 p.push(op[i]);
    }
    return p;
}
console.log(props(my_object)); // ["property1", "property2", "sample1", "sample2", "constructor", "toString", "toLocaleString", "valueOf", "hasOwnProperty", "isPrototypeOf", "propertyIsEnumerable"

Answer 2

function prototypeProperties(obj) {
  var result = [];
  for (var prop in obj) {
    if (!obj.hasOwnProperty(prop)) {
      result.push(prop);
    }
  }
  return result;
}

EDIT: This will grab all the properties that were defined on any ancestor. If you want a more granular control of what is defined where, Bergi's suggestion is good.