telephone number validator javascript
// Valid US Phone Number but can be tweaked.
const telephoneCheck = str => {
const regExp = /^1?\s?(\(\d{3}\)|\d{3})(\s|-)?\d{3}(\s|-)?\d{4}$/gm
return regExp.test(str)
}
telephoneCheck("27576227382");
/* Regular Expression Explanation Below !!! */
/*
Expression : /^1?\s?(\(\d{3}\)|\d{3})(\s|-)?\d{3}(\s|-)?\d{4}$/gm
^ asserts position at start of a line
1? matches the character 1 literally (case sensitive)
? Quantifier — Matches between zero and one times, as many times as possible, giving back as needed (greedy)
\s? matches any whitespace character (equal to [\r\n\t\f\v \u00a0\u1680\u2000-\u200a\u2028\u2029\u202f\u205f\u3000\ufeff])
? Quantifier — Matches between zero and one times, as many times as possible, giving back as needed (greedy)
1st Capturing Group (\(\d{3}\)|\d{3})
1st Alternative \(\d{3}\)
\( matches the character ( literally (case sensitive)
\d{3} matches a digit (equal to [0-9])
{3} Quantifier — Matches exactly 3 times
\) matches the character ) literally (case sensitive)
2nd Alternative \d{3}
\d{3} matches a digit (equal to [0-9])
{3} Quantifier — Matches exactly 3 times
2nd Capturing Group (\s|-)?
? Quantifier — Matches between zero and one times, as many times as possible, giving back as needed (greedy)
1st Alternative \s
\s matches any whitespace character (equal to [\r\n\t\f\v \u00a0\u1680\u2000-\u200a\u2028\u2029\u202f\u205f\u3000\ufeff])
2nd Alternative -
- matches the character - literally (case sensitive)
\d{3} matches a digit (equal to [0-9])
{3} Quantifier — Matches exactly 3 times
3rd Capturing Group (\s|-)?
? Quantifier — Matches between zero and one times, as many times as possible, giving back as needed (greedy)
1st Alternative \s
\s matches any whitespace character (equal to [\r\n\t\f\v \u00a0\u1680\u2000-\u200a\u2028\u2029\u202f\u205f\u3000\ufeff])
2nd Alternative -
\d{4} matches a digit (equal to [0-9])
{4} Quantifier — Matches exactly 4 times
$ asserts position at the end of a line
Global pattern flags
g modifier: global. All matches (don't return after first match)
m modifier: multi line. Causes ^ and $ to match the begin/end of each line (not only begin/end of string)
*/
// With love @kouqhar