Tonight's coding mission: implement deep copying to kill some rather ugly boilerplate

gistfile1.js

// From...
var TestForm = forms.formFactory({
  fields: function() {
    return {
      username: new forms.CharField(),
      password: new forms.CharField({widget: forms.PasswordInput})
    };
  },
  clean: function() {
    if (this.cleanedData.username && this.cleanedData.password &&
        (this.cleanedData.username != 'admin' ||
         this.cleanedData.password != 'secret')) {
      throw new forms.ValidationError('Invalid credentials!');
    }
    return this.cleanedData;
  }
});

// ...to...
var TestForm = forms.formFactory({
  username: new forms.CharField(),
  password: new forms.CharField({widget: forms.PasswordInput}),
  clean: function() {
    if (this.cleanedData.username && this.cleanedData.password &&
        (this.cleanedData.username != 'admin' ||
         this.cleanedData.password != 'secret')) {
      throw new forms.ValidationError('Invalid credentials!');
    }
    return this.cleanedData;
  }
});