Regex fails every second call [duplicate]

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• Why RegExp with global flag in Javascript give wrong results? 4 answers

I have a regex check which fails every second time that it is called.

const PHONE_REGEX = /^(0{0,2}|\+|[1-9])[1-9]\d{7,}$/g;
const validatePhoneNumber = (telNumber) => PHONE_REGEX.test(telNumber);

const input = "01695233966";

[ validatePhoneNumber(input), validatePhoneNumber(input), validatePhoneNumber(input), validatePhoneNumber(input) ]

I have tried replacing validatePhoneNumber calls with just PHONE_REGEX.test but I still experience the same issue.

via James Monger