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Extract the domain name from a URL (5kyu)

Instructions​

Write a function that when given a URL as a string, parses out just the domain name and returns it as a string. For example:

Examples​

domainName("http://github.com/carbonfive/raygun") == "github"
domainName("http://www.zombie-bites.com") == "zombie-bites"
domainName("https://www.cnet.com") == "cnet"

Sample Tests​

const { assert } = require("chai");

describe("Sample test", () => {
  it("Should pass sample tests", () => {
    assert.equal(domainName("http://google.com"), "google");
    assert.equal(domainName("http://google.co.jp"), "google");
    assert.equal(domainName("www.xakep.ru"), "xakep");
    assert.equal(domainName("https://youtube.com"), "youtube");
  });
});

Solution​

function domainName(url) {
  return url.replace(/((http:\/\/)|(https:\/\/))|(www.)/gm, "").split(".")[0];
}

Review​

정규식 정리

/((http:\/\/)|(https:\/\/))|(www.)/gm : http:// or https://로 시작하거나 www.는 선택인(있어도 되고 없어도 됨) 정규식

그리고 . 뒤를 전부 제거 하고 나머지 문자를 뱉음

References​

CodeWars - Extract the domain name from a URL (5kyu)