我怎样才能缩短这个if语句呢？

if (($('#first').val() != '') && ($('#middle').val() != '') && ($('#last').val() != '') && ($('#email').val() != '') && ($('#account_type').val() != '') && ($('#account_routing').val() != '') && ($('#account_number').val() != '')) {



}

此外，我还想在没有像这样的长语句的情况下检查空值。 我知道其他的方法，但就是不知道什么是最好的选择。

我试过了

var credit_map = {
    "#first": "First Name",
    "#middle": "Middle Name",
    "#last": "Last Name",
    "#email": "Email Address",
    "#postalcode": "Zip/Postal Code",
    "#card_name": "Name on Card",
    "#card_number": "Card Number",
    "#card_month": "Card Experation Month",
    "#card_year": "Card Experation Year",
    "#card_verification": "Card Verification Code"
}

for (var [key, value] of Object.entries(credit_map)) {
    if ($(key).val() != null || undefined) {

    }
}

我知道的方法:

![“a”, “b”, “c”].indexOf(“a”)

const​ student = {​ 
    name: ​'Bob’​,​ 
    equipmentTraining: ​''​,​ 
}
if​(!student.equipmentTraining) {​
    return​ ​'Not authorized to operate machinery'​
}