Validate JavaScript

Question

I am trying to validate 4 of these addresses. I tried multiple ways and they do not seem to be working. If I use a single address to compare it with, it works but multiple dont.

function validateAddress() {
    var address = document.forms["ipForm"]["address"].value;
    var error = "";
    var ip1 = "192.168.0.0";
    var ip2 = "192.168.0.1";
    var ip3 = "192.168.0.2";
    var ip4 = "192.168.0.3";


    if (!address.match(ip1)) {
        error += "Please enter a valid address \n";
    }

    else if (!address.match(ip2)) {
        error += "Please enter a valid address \n";
    }

    else if (!address.match(ip3)) {
        error += "Please enter a valid address \n";
    }

    else if (!address.match(ip4)) {
        error += "Please enter a valid address \n";
    }
    return error;
}

What do you mean "multiple don't"? Why should an address match more than one ip? — Teepeemm
– Teepeemm, Commented Nov 15, 2015 at 21:47

webdeb · Accepted Answer · 2015-11-15 20:08:33Z

1

Don't need match at all if you are not validating against a regEx. If there is just a set of valid options, then just test against the set with Array.indexOf

var input = "xyz"// Some user input 
var validIps = ["192.168.0.0", "192.168.0.1", "192.168.0.2", "192.168.0.3"];

if (validIps.indexOf(input) == -1) { // if this is not in set indexOf returns -1
  // error
}

answered Nov 15, 2015 at 20:08

webdeb

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jrkt · Accepted Answer · 2015-11-15 19:59:15Z

0

Use indexOf:

if (ip1.indexOf(address) === -1) { 
     error += " Please enter a valid address \n"; 
} else if (ip2.indexOf(address) === -1) { 
     error += "Please enter a valid address \n"; 
} else if (ip3.indexOf(address) === -1) {
     error += "Please enter a valid address \n"; 
} else if (ip4.indexOf(address) === -1) {
    error += "Please enter a valid address \n"; 
}

You could also make it much shorter by creating an array with the 4 IP addresses and then calling:

var array = ["192.168.0.0","192.168.0.1","192.168.0.2","192.168.0.3"];
if (array.indexOf(address) === -1) {
    //not valid
}

edited Nov 15, 2015 at 19:59

answered Nov 15, 2015 at 19:52

jrkt

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Comments

MinusFour · Accepted Answer · 2015-11-15 20:02:24Z

0

Looks like a good example for Array.prototype.some

var address = document.forms["ipForm"]["address"].value, 
    error,
    ips = ["192.168.0.0", "192.168.0.1", "192.168.0.2", "192.168.0.3"],
    match = ips.some(function(ip) {
        return address.match(ip) !== null;
    });

if(!match){
  error = "Please enter a valid address";
  }

edited Nov 15, 2015 at 20:02

answered Nov 15, 2015 at 19:58

MinusFour

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3 Comments

MinusFour Over a year ago

@webdeb, for some reason I thought there was an ip reference but it seems he was using address.

webdeb Over a year ago

Sorry, where does some come from?

MinusFour Over a year ago

It's from Array.prototype.some.

Darren Gourley · Accepted Answer · 2015-11-15 20:07:14Z

You need to revisit your logic. You will always get an error message returned. Let's say our address var is "bob". It does not match ip1 so the condition is true and we set the error message. Let's say our address var is "192.168.0.0". It does match ip1 so the condition of the first if statement will be false (because of the negation with !). We will go to the else if condition and try to match on ip2. Does it match? No, so the condition will be true and the error message will be set. You want to try something like

if(!address.match(ip1) && !address.match(ip2) && !address.match(ip3) && !address.match(ip4)) 
    { error += "Please enter a valid address \n";   }

Which is essentially: if address doesn't match ip1, 2, 3 or 4, then set the error message.

You might also want to explore the possibility of having the allow list stored in an array which you can iterate over. It would mean you wouldn't need another if statement or update your condition each time you add a new ip address to the allow list. With each iteration you can test the input address against each item in your array. If it matches you can return from the function early. If it does not match you can return the error message after you're done looping.

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