js检查许多不等于空的变量

Question

Maybe this is a duplicate question. But I didn't find any good answer at all. I want to check multiple variables if not equal to empty('') as below;

var list1 = '';
var list2 = 'something';
var list3 = '';
var list4 = 'hello world';

Now I want to check only one variable not equal empty returns true. If more than one variables are not empty returns false

As I tried

if(list1 != '' && list2 != '' && list3 != '' && list4 != ''){
   alert("ALL are filled");
   return false;
}

I have no idea how to do it with javascript logical operations

Answer 1

You can create an array and use filter + length to get the number of empty items:

 var list1 = ''; var list2 = 'something'; var list3 = ''; var list4 = 'hello world'; var list = [list1, list2, list3, list4]; var numberEmptyItens = list.filter((item) => item === '').length; console.log(numberEmptyItens);