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Randy Rivera
Randy Rivera

Posted on • Edited on

Validating Phone Numbers with JavaScript

#javascript #tutorial #beginners #devops
  • Here they want us to return true if the passed string looks like a valid US phone number. The person can fill out the form any way they choose as long as it has the valid format for a US Number.
  • The person may fill out the form field any way they want as long as it has the format of a valid US number. The following are examples of valid formats for US numbers. 
555-555-5555 (555)555-5555 (555) 555-5555 555 555 5555 5555555555 1 555 555 5555
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  • Code: 
function numberCheck(str) { return true; } numberCheck("555-555-5555");
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  • Answer: 
// 1- ^ beginning of the string. // 2- (1\s?)? allows for "1" or "1 " if there is one. // 3- \d{n} checks for exactly n number of digits so \d{3} // checks for three digits // 4. - x|y checks for either x or y so (\(\d{3}\)|\d{3} // checks for either three digits surrounded by parentheses or three digits by themselves with no parentheses // 5. [\s\-]? checks for spaces or dashes between the groups of digits. // 6. $ end of the string function numberCheck(str) { const regex = /^(1\s?)?(\d{3}|\(\d{3}\))[\s\-]?\d{3}[\s\-]?\d{4}$/ return regex.test(str) } numberCheck("1 555-555-5555"); will display true
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“Freecodecamp.org.” Edited by Quincy Larson, Telephone Number ValidatorPassed, Quincy Larson, 2014, www.freecodecamp.org/learn/javascript-algorithms-and-data-structures/javascript-algorithms-and-data-structures-projects/telephone-number-validator.

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