how to convert snake case to camel snake case javascript typescript

1var s1 = 'someTextHere';
2var o1 = s1.split(/(?=[A-Z])/).join('_').toLowerCase();

1function convertSnakeToCamelSnake(obj: any){
2  let newTokens = []
3  if (obj) {
4    Object.keys(obj).forEach( key => {
5      newTokens = []                                                                // Reset each loop
6      let tokens = key.split('_')
7      tokens.forEach( token => { newTokens.push(capitalizeFirstLetter(token)) });   // Capitalize first letter of each token
8      newTokens.join('')                                                            // Concatenate array indexes to string
9    });
10  }else{
11    console.log("Can not convert case of object:" + obj)
12  }
13  return newTokens
14}