According to the ASCII character encoding, there are 95 printable characters in total.
Those characters are in the range [0x20 to 0x7E] ([32 to 126] in decimal) and they represent letters, digits, punctuation marks, and a few miscellaneous symbols.
Character 0x20 (or 32 in decimal) is the space character ' ' and
character 0x7E (or 126 in decimal) is the tilde character '~'.
Source: https://en.wikipedia.org/wiki/ASCII#Printable_characters
Since all the printable characters of ASCII are conveniently in one continuous range, we used the following to filter all other characters out of our string in JavaScript.
printable_ASCII_only_string = input_string.replace(/[^ -~]+/g, "");
What the above code does is that it passes the input string through a regular expression which will match all characters out of the printable range and replace them with nothing (hence, delete them).
In case you do not like writing your regular expression with the space character to it, you can re-write the above regular expression using the hex values of the two characters as follows:
printable_ASCII_only_string = input_string.replace(/[^\x20-\x7E]+/g, "");