Regex for JavaScript Variable Name

javascript

const regex = /^[a-zA-Z_$][a-zA-Z0-9_$]*$/;
const isValid = regex.test(value);

python

import re
pattern = r'^[a-zA-Z_$][a-zA-Z0-9_$]*$'
if re.match(pattern, value):
    print("valid")

ruby

pattern = /^[a-zA-Z_$][a-zA-Z0-9_$]*$/
if value =~ pattern
  puts "valid"
end

php

if (preg_match('/^[a-zA-Z_$][a-zA-Z0-9_$]*$/', $value)) {
    echo "valid";
}

java

String pattern = "^[a-zA-Z_$][a-zA-Z0-9_$]*$";
boolean isValid = value.matches(pattern);