const snakeToCamelCase = (s) =>

  s.toLowerCase().replace(/(_\w)/g, (w) => w.toUpperCase().substr(1));

const str1 = 'learn_javascript';

console.log(snakeToCamelCase(str1)); 

type SnakeToCamelCase<S extends string> =

  S extends `${infer T}_${infer U}` ?

  `${T}${Capitalize<SnakeToCamelCase<U>>}` :

  S

import re

​

def camel_to_snake(s):

    return re.sub(r'(?<!^)(?=[A-Z])', '_', s).lower()

​

original_dict = {

    'testId': self.test_id,

    'valve': self.valve,

    'testType': self.test_type,

    'openingPress': self.opening_press,

    'closingPress': self.closing_press,

    'holdingPress': self.holding_press,

    'openingOk': self.opening_ok,

    'closingOk': self.closing_ok,

    'holdingOk': self.holding_ok,

    'testDate': self.test_date,

    'userCode': self.user_code

}

​

snake_case_dict = {camel_to_snake(key): value for key, value in original_dict.items()}

​

print(snake_case_dict)

using System.Text.RegularExpressions;

​

public class Program 

{

    public static string ToSnakeCase(string str) 

    {

            return Regex.Replace(str, "[A-Z]", "_$0").ToLower();

    }

    public static string ToCamelCase(string str) 

    {

              return  Regex.Replace(str, "_[a-z]", delegate(Match m) {

                    return m.ToString().TrimStart('_').ToUpper();

              });

    }

}