You can just use array.join(character to split with) to convert the array of social medias into a string list. In this case it would be

<td>{{ info.socialMedia.join(', ') }}</td>

Project link

to complete your goals you should use Array.join() method. Also, I strongly recommend you use MDN when looking for built-in methods.

In your case it will be look like:
<td>{{ info.socialMedia.join(', ') }}</td>

You can use join here to join array of strings as:

live DEMO

<td>{{ info.socialMedia.join(", ") }}</td>