Validation of 3 different inputs, and enabling submit button only when all are valid

Input validation with RxJs and rx.angular.js

/**
 * Handle send later input validation, and enabling/disabling the
 * submit button if all requirements are met
 * (all three fields are filled out and valid).
 */
$scope.formIsValid = false;

function returnNewvalue(data){
    return data.newValue;
}

var sendLaterDate = $scope.$toObservable('date')
    .map(returnNewvalue)
    .map(function (x) {
        //Simple test to match datepicker timestamp. ex: Wed Nov 16 2015 00:00:00 GMT+0100 (CET)
        return /^(\w+)\s(\w+)\s([0-9]+)\s([0-9]+)/.test(x);
    });

var sendLaterHour = $scope.$toObservable('hour')
    .map(returnNewvalue)
    .map(function (x) {
        return /^([0-1][0-9]|2[0-3])$/.test(x);
    });

var sendLaterMinute = $scope.$toObservable('minute')
    .map(returnNewvalue)
    .map(function (x) {
        return /^[0-5][0-9]$/.test(x);
    });

//Both date and time should both be valid before enabling the button:
Rx.Observable.combineLatest(date, hour, minute, function (x, y, z) {
    return x && y && z;
})
.subscribe(function (allValid) {
    $scope.formIsValid = allValid;
    if(allValid){
        //Enable save to outbox button
        jQuery("#sendsmsbutton")
            .removeClass("lightGrayBg")
            .addClass("greenBg")
            .removeClass("disabled");
    }else{
        jQuery("#sendsmsbutton")
            .removeClass("greenBg")
            .addClass("lightGrayBg")
            .addClass("disabled");
    }
});