Don't overwrite default options while making a copy

[markangelillo]

Object.assign needs the first parameter to be the target, so it should be an empty object in this case.

Run this sample code to see the issue:

class MyClass {
  constructor(options = {}) {
    this.options = Object.assign(MyClass.defaultOptions, options);
    this.staticProperty = options.staticProperty;
  }
}
MyClass.defaultOptions = {
    staticProperty: 'classDefault',
    anotherProperty: 'anotherDefault',
};

let a = new MyClass({staticProperty: 'classA'});
console.log(MyClass.defaultOptions);
let b = new MyClass({staticProperty: 'classB'});
console.log(MyClass.defaultOptions);