Hello Everyone,
I am a software programmer, I was wondering if there is an option to use the calculator via some js libraries.
I read somewhere on this site, that I can download, use and explore more when I register. However, I seem to have lost.
Can someone guide me to find the correct resource?

I am working on a POC to display calculators on an HTML page and I plan to support various calculators including ti84.

Any help would be appreciated.

Regards,
hT

jsTIfied in an online TI-83+/84+ emulator. You will still need access to a physical calculator in order to get the ROM image, which is required to use the emulator.

If I understand correctly, you want to make a website which allows people to use an Emulator?
In this case, please note you may not legally distribute the ROM image of the calculator. This is a protection so that you need to possess an actual physical calculator in order to use an emulator.
You may however implement it in the way jsTIfied works - do not distribute the ROM image, but rather prompt your users to upload their own.

What he said. Do note, however, that jsTIfied's license forbids it from being used outside of the Cemetech webpage, so you can forward your users to jsTIfied hosted on Cemetech, but cannot embed it on your own site.

If you absolutely must host it on your web page, you can take a look at OpenTI which is under the MIT license. From what I understand the underlying emulator code is written in C and OpenTI is just a web wrapper around it.

Writing the underlying emulator code in a language which compiles to native code, and using Emscripten to transpile it to asm.js or better nowadays, WebAssembly, is indeed the right approach, and has been for a while.
Back in the day, when there was not even asm.js yet, we had to write / generate JS manually, occasionally fight general weirdness in the JS language itself, and try to perform optimization on the moving targets full of insanity that the JIT engines of modern browsers are... been there, done that, it was bad