declare var ko: KnockoutStatic;

interface KnockoutStatic {
    protectedObservable: (initialValue: any) => any;
    dependentObservable(p: { read: KnockoutObservable<any>; write: (newValue: any) => void });
}

interface KnockoutObservable<T> {
    protectedObservable: (initialValue: any) => any;
    reset: () => void;
    commit: (vaule?: any) => void;
}

ko.protectedObservable = (initialValue) => {
    let temp = initialValue;
    const actual = ko.observable(initialValue);

    const result = ko.dependentObservable({
        read: actual,
        write: (newValue) => {
            temp = newValue;
        }
    }).extend({ notify: 'always' });

    result.commit = (value?: any) => {
        if (value) {
            actual(value);
        } else {
            if (temp !== actual()) {
                actual(temp);
            }
        }
    };

    result.reset = () => {
        actual.valueHasMutated();
        temp = actual();
    };

    return result;
};