Using a method includes() checking string for occurrences of characters represented in array is returning true - removing characters from a string

Question

I'm building a URL slug generator and I need to have the behavior be that if what's inputted is:

Ok Now Let's Do This & See

the output needs to be

ok-now-lets-do-this-see

Removing the & , ', and , characters

let newStr;

function slugifyString(str) {
  let forbiddenChars = ["&", "'", ","];
    newStr = str.toLowerCase().replace(/\s/g, '-');
  if (newStr.includes(forbiddenChars) > -1) {
    console.log('a forbidden character is present')
  }
}

document.getElementById('slug-a-string-form').addEventListener('submit', function(e) {
  e.preventDefault();
  let inputStr = document.getElementById('string-to-slug').value
  slugifyString(inputStr);
  document.getElementById('slugged-string').innerHTML = newStr;
});

#slugged-string {
  color: green;
  font-size: 15px;
  padding-top: 20px;
}

<form id="slug-a-string-form" action="POST">
  <input type="text" id="string-to-slug" placeholder="enter the string to want to slug here...">
  <input type="submit" value="Submit">
</form>

<div id="slugged-string"></div>

This works with a string like:

Testing This Out With Something TitleLike

And it slugifies, but it's saying that a forbidden character is present when it's not. Why is that happening?

How to check if a string contains text from an array of substrings in JavaScript?

I tweaked it a bit and tried this:

let newStr;

function slugifyString(str) {
  let forbiddenChars = ["&", "'", ","];
    newStr = str.toLowerCase().replace(/\s/g, '-');
  let forbiddenCharsLength = forbiddenChars.length;
    while(forbiddenCharsLength--) {
    if (newStr.indexOf(forbiddenChars[forbiddenCharsLength])!=-1) {
      if(forbiddenChars[forbiddenCharsLength] == "&") {
        newStr = newStr.replace("-&", '')
      } else {
        newStr = newStr.replace(forbiddenChars[forbiddenCharsLength], '')
      }
    }
  }
}

document.getElementById('slug-a-string-form').addEventListener('submit', function(e) {
  e.preventDefault();
  let inputStr = document.getElementById('string-to-slug').value
  slugifyString(inputStr);
  document.getElementById('slugged-string').innerHTML = newStr;
});

#slugged-string {
  color: green;
  font-size: 15px;
  padding-top: 20px;
}

<form id="slug-a-string-form" action="POST">
  <input type="text" id="string-to-slug" placeholder="enter the string to want to slug here...">
  <input type="submit" value="Submit">
</form>

<div id="slugged-string"></div>

Based on the output of the console:

it is: '
it is: &

It appears to be looping over each iteration of a forbidden character.

Inputting in:

Ok Now Let's Do This & See

We get the correct output now of:

ok-now-lets-do-this-see

But if we say:

Ok Now Let's Do This & That & See, what happens if we have more than one, comma

We get:

ok-now-lets-do-this-that-&-see-what-happens-if-we-have-more-than-one,-comma

I'm not sure why it's not removing every character that's forbidden, since we're looping over it.

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/replace

If pattern is a string, only the first occurrence will be replaced.

I do know that it replaces it only once, but

while(forbiddenCharsLength--) {
    if (newStr.indexOf(forbiddenChars[forbiddenCharsLength])!=-1) {
      if(forbiddenChars[forbiddenCharsLength] == "&") {
        newStr = newStr.replace("-&", '')
      } else {
        newStr = newStr.replace(forbiddenChars[forbiddenCharsLength], '')
      }
    }

We're doing a while loop and executing an if command on each match so shouldn't the replace run for each instance..?

What am I missing here?

score 1 · Accepted Answer · answered Oct 19 '21 at 18:07

1

Try use replaceAll function instead of replace.

answered Oct 19 '21 at 18:07

Garik Harutyunyan

121
3

Ugh I always forget all the different methods, I'm accepting this one as soon as I can – kawnah Oct 19 '21 at 18:09

score 1 · Answer 2 · answered Oct 19 '21 at 18:08

1

You might want to try this solution:

const s = "Ok Now Let's Do This & That & See, what happens if we have more than one, comma";

const slug = s.replaceAll(/[',&]/g, '').replaceAll(/\s+/g, '-').toLowerCase();

console.log(slug);

answered Oct 19 '21 at 18:08

majusebetter

1,458
1
4
13

score 0 · Answer 3 · answered Oct 19 '21 at 18:07

You can split the string into an array for each letter, then remove (map to "") each forbidden letter and proceed by replacing whitespaces with -

  let forbiddenChars = ["&", "'", ","];
  let newStr = str
    .toLowerCase()
    .split("")
    .map(ch => forbiddenChars.includes(ch) ? '' : ch)
    .join("")
    .replace(/\s/g, '-');

function slugifyString(str) {
  let forbiddenChars = ["&", "'", ","];
  let newStr = str
    .toLowerCase()
    .split("")
    .map(ch => forbiddenChars.includes(ch) ? '' : ch)
    .join("")
    .replace(/\s/g, '-');
  if (newStr.includes(forbiddenChars) > -1) {
    console.log('a forbidden character is present')
  }
  return newStr;
}

document.getElementById('slug-a-string-form').addEventListener('submit', function(e) {
  e.preventDefault();
  let inputStr = document.getElementById('string-to-slug').value
  let outputStr = slugifyString(inputStr);
  document.getElementById('slugged-string').innerHTML = outputStr;
});

#slugged-string {
  color: green;
  font-size: 15px;
  padding-top: 20px;
}

<form id="slug-a-string-form" action="POST">
  <input type="text" id="string-to-slug" placeholder="enter the string to want to slug here...">
  <input type="submit" value="Submit">
</form>

<div id="slugged-string"></div>

score 0 · Answer 4 · answered Oct 19 '21 at 18:16

You could iterate the array with unwanted characters/substrings and replace the final spaces with dashes.

function slugify(s) {
    return ['&', ',', '\'']
        .reduce((s, c) => s.replaceAll(c, ' '), s)
        .replace(/\s+/g, '-');
}

console.log(slugify('Ok Now Let\'s Do This & That & See, what happens if we have more than one, comma'));

Using a method includes() checking string for occurrences of characters represented in array is returning true - removing characters from a string

4 Answers4