# [JavaScript] Data Structures and Modern Operators: Coding Challenge #4

Write a program that receives a list of variable names written in underscore_case
and convert them to camelCase.
The input will come from a ```
textarea
``` inserted into the DOM (see code below to
insert the elements), and conversion will happen when the button is pressed.
Test data (pasted to ```
textarea
```, including spaces):

```
underscore_case
  first_name
Some_Variable
    calculate_AGE
delayed_departure
```

Should produce this output (5 separate console.log outputs):
```
underscoreCase     ✅
firstName          ✅✅
someVariable       ✅✅✅
calculateAge       ✅✅✅✅
delayedDeparture   ✅✅✅✅✅
```

Hints:
§ Remember which character defines a new line in the ```textarea``` 😉

§ The solution only needs to work for a variable made out of 2 words, like a_b

§ Start without worrying about the ✅. Tackle that only after you have the variable
name conversion working 😉

§ This challenge is difficult on purpose, so start watching the solution in case
you're stuck. Then pause and continue!

Afterward, test with your own test data!
GOOD LUCK 😀

Given codes for inserting elements:
```
document.body.append(document.createElement('textarea'));
document.body.append(document.createElement('button'));

const text = document.querySelector('textarea').value;
```

* Codes

```
document.body.append(document.createElement('textarea'));
document.body.append(document.createElement('button'));

// Recommended answer
 document.querySelector('button').addEventListener('click', function () {
   const text = document.querySelector('textarea').value;
   const rows = text.split('\n');

   for (const [i, row] of rows.entries()) {
     const [first, second] = row.toLowerCase().trim().split('_');

     const output = `${first}${second.replace(
       second[0],
       second[0].toUpperCase()
     )}`;
     console.log(`${output.padEnd(20)}${'✅'.repeat(i + 1)}`);
   }
 });

// Tried answer
document.querySelector('button').addEventListener('click', function () {
  const text = document.querySelector('textarea').value;
  const rows = text.split('\n');

  for (const [i, row] of rows.entries()) {
    const [first, second] = row.split('_');
    const secondTextUpper = [];
    secondTextUpper.push(first.replace(first, first.toLowerCase()));
    secondTextUpper.push(second.replace(second[0], second[0].toUpperCase()));
    console.log(
      `${secondTextUpper.join('').trim().padEnd(20)}${'✅'.repeat(i + 1)}`
    );
  }
});
```
* Result

![coding challenge 4.PNG](https://cdn.hashnode.com/res/hashnode/image/upload/v1655274300965/AWTfRJW6J.PNG align="left")