Show me the actual regex implementation that escapes special characters.

The actual regex implementation is in [index.js:L8-L11]:

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

This implementation uses two regex replacements:

1. First replacement [|\\{}()[\]^$+*?.]/g — Escapes the common RegExp special characters by prefixing them with a backslash (\\$&). The character class matches:

   • | (alternation)
   • \ (backslash)
   • {} (quantifier braces)
   • () (grouping parentheses)
   • [] (character class brackets)
   • ^ (anchor/negation)
   • $ (end anchor)
   • +*?. (quantifiers and literal dot)

2. Second replacement /-/g — Escapes hyphens using \x2d (hex escape) instead of a simple backslash. This is done for compatibility with PCRE and Unicode flag patterns, as shown in the test cases [test.js:L10-L20].

The function also includes type checking to ensure the input is a string [index.js:L2-L4].

FOLLOW_UPS:

• Why does hyphen use \x2d instead of backslash?
• What RegExp characters are NOT escaped by this function?
• How does this differ from native RegExp.escape()?