freeCodeCamp | JavaScript Algorithms and Data Structures Projects: Telephone Number Validator: Return true if the passed string looks like a valid US phone number. The user may fill out the form field any way they choose as long as it has the format of a valid US number. The following are examples of valid formats for US numbers (refer to the te…

Project-Telephone-Number-Validator.js

function telephoneCheck(str) {
  // regex that matches a phone number with no spaces,
  // with spaces, with dashes, and with or without country code
  let regex = /^[1]*[\s|-]*\d{3}[\s|-]*\d{3}[\s|-]*\d{4}$/;

  // regex that matches parentheses
  // with no spaces, with spaces, with dashes,
  // and with or without country code
  let regexParentheses = /^[1]*[\s]*[(]\d{3}[)][\s]*\d{3}[\s|-]*\d{4}$/;

  if (!regex.test(str)) {
    return regexParentheses.test(str);
  } else {
    return true;
  }

}

telephoneCheck("1 (555) 555-5555"); // returns true
telephoneCheck("1 555)555-5555") // returns false

excellent

why is the last one return false

why is the last one return false

Last one is not considered valid because there is no opening bracket.

Para validar también el último caso deberíamos aregar: ^[1]?
Es decir el patrón quedaría así -> /^[1]?(\s)(\d{3})+[-|\s](\d{3})+[-|\s]*\d{4}$/;
Con '?' nos aseguramos que si viene el 1, sea 1 vez.

Got it in 1 line if anyone is interested:
return /^(1 |1)?((\d{3})|(\(\d{3}\)))(-| |)(\d{3})(-| |)(\d{4})$/.test(str)

Another way:

function telephoneCheck(str) {
let regex = /^(1 |1)?((\d{3})|((\d{3})))(-| |)(\d{3})(-| |)(\d{4})$/;
return (regex.test(str)==true)
}
console.log(telephoneCheck("1 (555) 555-5555")) // returns true
console.log(telephoneCheck("1 555)555-5555")) // returns false

Got it in 1 line if anyone is interested: return /^(1 |1)?((\d{3})|(\(\d{3}\)))(-| |)(\d{3})(-| |)(\d{4})$/.test(str)

very very good^ super

Got it in 1 line if anyone is interested: return /^(1 |1)?((\d{3})|(\(\d{3}\)))(-| |)(\d{3})(-| |)(\d{4})$/.test(str)

very very good^ super

@RihardXXX Thanks for that, I was going the long route.

Got it in 1 line if anyone is interested:
return /^(1 |1)?((\d{3})|((\d{3})))(-| |)(\d{3})(-| |)(\d{4})$/.test(str)

You are incredible.

alternative:``

function telephoneCheck(str) {
  let regex = /^(1\s?)?(\(\d{3}\)|\d{3})([\s\-]?)\d{3}([\s\-]?)\d{4}$/;
  return regex.test(str);
}

console.log(telephoneCheck("1 (555) 555-5555")); // returns true
console.log(telephoneCheck("1 555)555-5555")); // returns false

return /^(1 |1)?((\d{3})|((\d{3})))(-| |)(\d{3})(-| |)(\d{4})$/.test(str)

Thanks a lot...your supperb.

Got it in 1 line if anyone is interested: return /^(1 |1)?((\d{3})|(\(\d{3}\)))(-| |)(\d{3})(-| |)(\d{4})$/.test(str)

Wonderfully done!