Add more features to the Javascript Calculator

[t1nt1n-s0lv3r]

There is only basic math functionalities implemented in the calculator I would like to add more trignometric functionalities and some features similar to scientific calculator

Please assign me this issue @iamrahulmahato Please assign it under gssoc extd and hacktoberfest

[rutikakengal]

I would like add more functionalities to the calculator and Assign me i loved to work on this

[t1nt1n-s0lv3r]

@iamrahulmahato has my pr worked properly as this was my first time doing open source