Explanation: [ -~] is matching the range of characters† from space (32) to tilde (126), which is the full range of printable ASCII characters. (0–31 are various

Explanation: [ -~] is matching the range of characters† from space (32) to tilde (126), which is the full range of printable ASCII characters. (0–31 are various control characters, and 127 is one last control character, ␡.) † “Characters” is a deliberately vague term here. Different regular expression engines match different types of things, typically supporting one or two modes. The three most common things to match are bytes (the traditional default, normally encoding-unaware but potentially known to be ASCII or UTF-8), UTF-16 code units (JavaScript’s default, and UTF-16 was an all-round terrible idea that ruined Unicode for everyone else while achieving nothing useful), and Unicode scalar values (which is typically called “Unicode mode” and often enabled by a /u flag).