How does Online Font/Text Converter for Social Networks work?

Question

JavaScript

The task is to implement a font converter for social networks like https://fsymbols.com/generators/
i.e. we enter text, for example "about", and as a result we should get something like a̷̶b̷̶o̷̶u̷̶t̷̶
There is an idea that there is a substitution of characters from the unicode table. But if you see an example in more detail, then a few more effects can be imposed on one text with an effect, for example A̶̶̶̶̶̶̶̶̶̶̶̷̶̲b̶̶̶̶̶̶̶̶̶̶̶̷̶̲o̶̶̶̶̶̶̶̶̶̶̶̷̶̲u̶̶̶̶̶̶̶̶̶̶̶̷̶̲t̶̶̶̶̶̶̶̶̶̶̶̷̶̲.
Can anyone please tell me how this works?
There is also another version of the example https://ru.piliapp.com/cool-text/strikethrough-text/ - here the text is underlined/strikethrough. Is the principle different from the first example?

Answer 1

On their side, a list of familiar characters is simply compared with a list of their variations in Unicode.
+ universal list of modifier characters applied to the previous character
in "a̶̶̶̶̶̶̶̶̶̶̶̷̶̲" included:
U+0061 LATIN SMALL LETTER A
U+0332 COMBINING LOW LINE
U+0336 COMBINING LONG STROKE OVERLAY
U+0337 COMBINING SHORT SOLIDUS OVERLAY