Show me the actual regex implementation that escapes special characters.

The regex implementation is in [index.js:L9-L10]:

return string
	.replace(/[|\\{}()[\]^$+*?.]/g, '\\$&')
	.replace(/-/g, '\\x2d');

This uses two replacement operations:

1. First replace [|\\{}()[\]^$+*?.]/g — Escapes the main RegExp special characters by adding a backslash before each one. The character class includes: |, \, {, }, (, ), [, ], ^, $, +, *, ?, and .. The \\$& replacement inserts a backslash before the matched character.

2. Second replace /-/g — Escapes the hyphen character as \x2d (hex escape) rather than a simple backslash. This is done to maintain compatibility with PCRE (Perl-Compatible Regular Expressions) and the Unicode flag, as the test cases verify [test.js:L10-L18].

The function first validates the input is a string [index.js:L2-L4], then applies these two replacements to safely escape all special characters.

FOLLOW_UPS:

• What characters are considered RegExp special characters?
• Why is hyphen escaped differently than other characters?
• What is the purpose of the \xnn escape format?