if array does not contain string

Question

I'am making a user registration page, and I don't want any char's that does not match the array.

function create(){
var allowed = [
"A","B","C","D","E","F","G","H","I","J","K","L","M","N","O","P","Q","R","S","T","U","V","W","X","Y","Z",
"a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p","q","r","s","t","u","v","w","x","y","z",
"1","2","3","4","5","6","7","8","9","0","_","-"];

var username = $("#username").val();

if (username == ""){
document.getElementById("usernameerror").style.color = "red";
document.getElementById("usernameerror").innerHTML = " Username cannot be blank.";
}else{

if (username.indexOf(allowed) != -1){
document.getElementById("usernameerror").style.color = "red";
document.getElementById("usernameerror").innerHTML = " No symbols.";
}else{
document.getElementById("usernameerror").style.color = "blue";
document.getElementById("usernameerror").innerHTML = " ✔";
}

}

}

I bet it's something simple.. (not sub string)

Probably easier to use a regex, but if you really want to do it with an array, you'd need to loop through each character in the string and check if all of them are in the array. Something like username.every(c => allowed.indexOf(c) > -1) if you're using ES6. — Heretic Monkey
– Heretic Monkey, Commented Jan 5, 2017 at 20:06
Are you using this array? If so did you really want to restrict all these characters. Or are you testing against a preset or user created array? — andre mcgruder
– andre mcgruder, Commented Jan 5, 2017 at 20:08
Possible duplicate of Javascript. Checking if string contains text from an array of substrings — Heretic Monkey
– Heretic Monkey, Commented Jan 5, 2017 at 20:08

jmar777 · Accepted Answer · 2017-01-05 20:08:50Z

3

This is exactly the kind of problem that regular expressions are designed to solve. Try replacing this line:

if (username.indexOf(allowed) != -1){

...with this:

if (!/^[a-z0-9_-]*$/i.test(username)) {

Your requirements are very similar to the \w metacharacter as well, which would let you alternatively use this for your regex:

/^[\w-]+$/

answered Jan 5, 2017 at 20:08

jmar777

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1 Comment

Marluxiaz Over a year ago

/^[\w-]+$/ Perfect.

benbotto · Accepted Answer · 2017-01-05 20:13:46Z

2

How about:

if (username.match(/[^\w-]/) !== null) {
  console.log('username has non-word characters...');
}

See here for what \w does: MDN Regular Expression.

edited Jan 5, 2017 at 20:13

answered Jan 5, 2017 at 20:08

benbotto

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1 Comment

jmar777 Over a year ago

This will fail if it encounters a - character, which was included in the OP's "allowed" list.

motanelu · Accepted Answer · 2017-01-05 20:09:21Z

0

Check this out:

if (/^[a-z0-9\-\_]+$/.test(username)) {
  document.getElementById("usernameerror").style.color = "red";
  document.getElementById("usernameerror").innerHTML = " No symbols.";
}else{
  document.getElementById("usernameerror").style.color = "blue";
  document.getElementById("usernameerror").innerHTML = " ✔";
}

answered Jan 5, 2017 at 20:09

motanelu

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1 Comment

Marluxiaz Over a year ago

This works for me, Thank you for adding it into my code makes it so much easier to work with. I changed: if (/^[a-z0-9\-\_]+$/.test(username)) { to if (/^[a-z0-9A-Z\-\_]+$/.test(username)) {

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