How to filter array item based on string with regex?

Question

The purpose of filter() is to remove currentGroup matching with URLs from the array. It doesn't matter there is numbers after Malappuram/123456/12 or not. Is there any best way to do it in ES6 ?

DEMO: https://jsbin.com/jozuqameto/edit?js,console

const initialLinks = [
  "http://www.lchfmalayalam.com",
  "https://t.me/Malappuram",
  "https://t.me/keraladevelopers/42716",
  "http://www.whatsapp.com",
  "https://www.youtube.com/watch?v=BnbFRSyHIl4",
  "http://google.com",
  "https://t.me/joinchat/NHNd1hcSMCoYlnZGSC_H7g",
  "https://t.me/keraladevelopers/",
  "http://t.me/keraladevelopers",
  "http://athimannil.com/react/",
  "http://athimannil.info/",
  "https://t.me/hellomates/5",
  "http://t.me/Malappuram/32156",
  "http://t.me/keraladevelopers/42716",
  "http://t.me/joinchat/NHNd1hcSMCoYlnZGSC_H7g",
  "http://t.me/keraladevelopers/",
  "http://t.me/hellomates/5"
];

const normalizeTme = R.replace(
  /^(?:@|(?:https?:\/\/)?(?:t\.me|telegram\.(?:me|dog))\/)(\w+)(\/.+)?/i,
  (_match, username, rest) => {
    return /^\/\d+$/.test(rest) ?
      `https://t.me/${username.toLowerCase()}` :
      `https://t.me/${username.toLowerCase()}${rest || ""}`;
  }
);

const filterOwnLinks = groupUsername => {
  return R.match(
    /^(?:@|(?:https?:\/\/)?(?:t\.me|telegram\.(?:me|dog))\/)(\w+)(\/.+)?/i,
    (_match, username, rest) => {
      if (username) {
        return currentGroup.toLowerCase() !== username.toLowerCase();
      }
      return true;
    }
  );
};

const currentGroup = "Malappuram";

const urls = R.uniq(initialLinks)
  .filter(filterOwnLinks)
  .map(normalizeTme);

console.log(initialLinks);
console.log(urls);

<script src="https://cdnjs.cloudflare.com/ajax/libs/ramda/0.25.0/ramda.min.js"></script>

How complex is the content of currentGroup? Do you really need Regular Expressions or is a good ol' indexOf operation enough? — StefanN
– StefanN, Commented Aug 8, 2019 at 11:39
It is actually for Telegram Bot, the currentGroup may vary at based on group name. The purpose is to filter link of the same group name related. — Mo.
– Mo., Commented Aug 8, 2019 at 11:41
Does the current group always appear after http://websitname.domain/currentGroup ? or it can be at any place in URL ? — Code Maniac
– Code Maniac, Commented Aug 8, 2019 at 12:18
@Mo. you can use URL api, and take pathname from parsed url and check if it starts with currentGroup — Code Maniac
– Code Maniac, Commented Aug 8, 2019 at 12:49

Code Maniac · Accepted Answer · 2019-08-08 13:53:30Z

1

You can use URL api to parse url, and take the pathname from parse url object, and check if starts with currentGroup

const initialLinks = ["http://www.lchfmalayalam.com","https://t.me/Malappuram","https://t.me/keraladevelopers/42716","http://www.whatsapp.com","https://www.youtube.com/watch?v=BnbFRSyHIl4","http://google.com","https://t.me/joinchat/NHNd1hcSMCoYlnZGSC_H7g","https://t.me/keraladevelopers/","http://t.me/keraladevelopers","http://athimannil.com/react/","http://athimannil.info/","https://t.me/hellomates/5","http://t.me/Malappuram/32156","http://t.me/keraladevelopers/42716","http://t.me/joinchat/NHNd1hcSMCoYlnZGSC_H7g","http://t.me/keraladevelopers/","http://t.me/hellomates/5"];
const currentGroup = "Malappuram";
const urls = [...new Set(initialLinks)]

let final = urls.filter(url => {
  let parsed = new URL(url)
  let pattern = new RegExp(`^\/${currentGroup}`,'i')
  return !pattern.test(parsed.pathname)
})

console.log(final)

edited Aug 8, 2019 at 13:53

answered Aug 8, 2019 at 12:53

Code Maniac

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3 Comments

Mo. Over a year ago

Thanks for your response👍 Actually I need to get the result with all links except currentGroup. Just make change !pattern.test(parsed.pathname) will be okay isn't ? ?

Mo. Over a year ago

what if we use .startsWith() ?

Code Maniac Over a year ago

@Mo. yes you can there are many ways you can achieve same thing, if you want to use startsWith you need to change case of both pathname and currentGroup to achieve case insensitivity, parsed.pathname.toLowerCase(`\/${currentGroup.toLowerCase()}`)

Tom O. · Accepted Answer · 2019-08-08 17:16:40Z

You could test with a simple regular expression within the Array.prototype.filter callback:

const initialLinks = [
  "http://www.lchfmalayalam.com",
  "https://t.me/Malappuram",
  "https://t.me/keraladevelopers/42716",
  "http://www.whatsapp.com",
  "https://www.youtube.com/watch?v=BnbFRSyHIl4",
  "http://google.com",
  "https://t.me/joinchat/NHNd1hcSMCoYlnZGSC_H7g",
  "https://t.me/keraladevelopers/",
  "http://t.me/keraladevelopers",
  "http://athimannil.com/react/",
  "http://athimannil.info/",
  "https://t.me/hellomates/5",
  "http://t.me/Malappuram/32156",
  "http://t.me/keraladevelopers/42716",
  "http://t.me/joinchat/NHNd1hcSMCoYlnZGSC_H7g",
  "http://t.me/keraladevelopers/",
  "http://t.me/hellomates/5"
];

const getCurrentGroupLinks = (links, regex) => {
  return links.filter(link => !regex.test(link));
};

console.log(getCurrentGroupLinks(initialLinks, /Malappuram/));

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