How can I get all "dirty" (modified) fields using angular2 forms?

Question

I can't find out how to retrieve all fields modified by the user using angular2 forms. I did some research here and on angular2 official forms docs and I couldn't find such information.

This is how I do it using jQuery:

    this.isFormDirty = function (form) {
        var changeNames = [];

        $(form).find(":input:not(:button):not([type=hidden])").each(function () {
            if ((this.type == "text" || this.type == "textarea" || this.type == "number" || this.type == "hidden" || this.type == "file") && this.defaultValue != this.value) {
                changeNames.push(this.name);
            } else {
                if ((this.type == "radio" || this.type == "checkbox") && this.defaultChecked != this.checked) {
                    changeNames.push(this.name);
                } else {
                    if ((this.type == "select-one" || this.type == "select-multiple")) {
                        for (var x = 0; x < this.length; x++) {
                            if (this.options[x].selected != this.options[x].defaultSelected) {
                                changeNames.push(this.name);
                            }
                        }
                    }
                }
            }
        });

        return changeNames;
    };

Is there a way to do that using angular2 forms? I thought I'd have some sort of changedValues property, but I can't find it.

EDIT

This is how my form is created: (permissionForm is of type FormGroup)

this.permissionForm = this.fb.group({
      FullUrl: ['', Validators.required],
      Area: ['', Validators.required],
      Controller: ['', Validators.required],
      Action: ['', Validators.required],
      Name: ['', Validators.required],
      Description: ['', Validators.required],
      ParentPermissionId: ['', Validators.required],
      ShowInMenu: ['', Validators.required],
      Order: ['', Validators.required],
      Icon: ['', Validators.required]
    });

Answer 1

const keyValue = Object.entries(this.form.controls).filter(value => value[1].dirty);

For get control names array:

keyValue.map(value => value[0]);

For get controls array:

keyValue.map(value => value[1]);

For get controls object:

keyValue.reduce((a, v) => Object.assign(a, { [v[0]]: v[1] }), {});

Сompact function:

type GetDirtyControlsTypes = 'object' | 'array' | 'names';

export function getDirtyControls(form: FormGroup, type: GetDirtyControlsTypes = 'object') {
  // keyValue
  const kv = Object.entries(form.controls).filter(val => val[1].dirty);
  return {
    object: () => kv.reduce((accum, val) => Object.assign(accum, { [val[0]]: val[1] }), {}),
    array: () => kv.map(val => val[1]),
    names: () => kv.map(val => val[0]),
  }[type]();
}