Tips for using "if not equal" with multiple items in JavaScript

Question

I have a simple question that I've been thinking about. Is there a way to accomplish the following:

If i is not equal to 1, 2, or 3, then alert('yes');

Can we achieve it using the following code:

if (!(i==1&2&3)) { alert('yes')}

Instead of the following longer version:

if (!((i==1) || (i==2) || (i ==3) )) { alert('yes');}

Answer 1

Answer №1

Consider using a switch statement, but it's important to understand your goal.

switch (i) {
    case 1:
    case 2:
    case 3:
        break;
    default:
        alert(yes);
}

Another approach could be a lookup table like this:

var x = {
    1: true,
    2: true,
    3: true
};

if (!x[i]) {
    alert('yes');
}

If you prefer strict testing with just a few conditions, you can do:

if (i !== 1 && i !== 2 && i !== 3) {
    alert('yes');
}

Answer 2

Consider using a switch statement, but it's important to understand your goal.

switch (i) {
    case 1:
    case 2:
    case 3:
        break;
    default:
        alert(yes);
}

Another approach could be a lookup table like this:

var x = {
    1: true,
    2: true,
    3: true
};

if (!x[i]) {
    alert('yes');
}

If you prefer strict testing with just a few conditions, you can do:

if (i !== 1 && i !== 2 && i !== 3) {
    alert('yes');
}

Answer 3

Try creating an array and utilizing the indexOf() method

if([1,2,3].indexOf(i) < 0){
    alert('yes');
}

If the returned value is greater than -1, it indicates that i is present in the array.

This alternative approach:

if (!(i=1&2&3)) { alert('yes')}

Might not achieve your intended outcome as 1&2&3 represents a bitwise AND operation, and there is only one = operator being used.

Answer 4

Try creating an array and utilizing the indexOf() method

if([1,2,3].indexOf(i) < 0){
    alert('yes');
}

If the returned value is greater than -1, it indicates that i is present in the array.

This alternative approach:

if (!(i=1&2&3)) { alert('yes')}

Might not achieve your intended outcome as 1&2&3 represents a bitwise AND operation, and there is only one = operator being used.