regex-utilities

Tiny utilities shared by the regex library and its plugins. Useful for parsing and processing regular expression syntax in a lightweight way, when you don't need a full regex AST.

Constants

Context

Frozen object with the following properties for tracking regex syntax context:

• DEFAULT - Base context.
• CHAR_CLASS - Character class context.

Functions

For all of the following functions, argument expression is the target string, and needle is the pattern to search for.

• Argument expression is assumed to be a flag-v-mode regex pattern string (in other words, nested character classes are allowed when determining the context for a match).
• Argument needle is a regex pattern as a string, and is applied with flags su.
• If argument context is not provided, matches are allowed in all contexts (in other words, inside and outside of character classes).

execUnescaped

Arguments: expression, needle, [pos = 0], [context]

Returns a match object for the first unescaped instance of a regex pattern in the given context, or null.

hasUnescaped

Arguments: expression, needle, [context]

Checks whether an unescaped instance of a regex pattern appears in the given context.

forEachUnescaped

Arguments: expression, needle, callback, [context]

Runs a callback for each unescaped instance of a regex pattern in the given context.

replaceUnescaped

Arguments: expression, needle, replacement, [context]

Replaces all unescaped instances of a regex pattern in the given context, using a replacement string or callback.

replaceUnescaped('.\\.\\\\.[[\\.].].', '\\.', '~');
// → '~\\.\\\\~[[\\.]~]~'

replaceUnescaped('.\\.\\\\.[[\\.].].', '\\.', '~', Context.DEFAULT);
// → '~\\.\\\\~[[\\.].]~'

replaceUnescaped('.\\.\\\\.[[\\.].].', '\\.', '~', Context.CHAR_CLASS);
// → '.\\.\\\\.[[\\.]~].'

getGroupContents

Arguments: expression, contentsStartPos

Extracts the full contents of a group (subpattern) from the given expression, accounting for escaped characters, nested groups, and character classes. The group is identified by the position where its contents start (the string index just after the group's opening delimiter). Returns the rest of the string if the group is unclosed.