@computed
    get completedPin() {
        const {_enteredDigits, _pinLength} = this;
        return _enteredDigits.length === _pinLength ?
            _enteredDigits.join('') :
            null;
    }
/**
     * The completed PIN entered by the user.  Observe this property to track the state
     * of user progress.
     *
     * @returns {string} - null if the user has not finished entering a PIN, otherwise the PIN
     *      the user entered.
     */
The completed PIN entered by the user.  Observe this property to track the state
of user progress.

@returns {string} - null if the user has not finished entering a PIN, otherwise the PIN
the user entered.
The completed PIN entered by the user . Observe this property to track the state of user progress . @returns { string } - null if the user has not finished entering a PIN otherwise the PIN the user entered .
@computed
    get completedPin() {
        const {_enteredDigits, _pinLength} = this;
        return _enteredDigits.length === _pinLength ?
            _enteredDigits.join('') :
            null;
    }
@ computed get completedPin ( ) { const { _enteredDigits , _pinLength } = this ; return _enteredDigits . length === _pinLength ? _enteredDigits . join ( '' ) : null ; }
The completed PIN entered by the user.
The completed PIN entered by the user .