Regex for multiline text area

Question

I am trying to validate text area. Format should be us following:

Text description: ${VARIABLE_NAME} \n
Text description: ${VARIABLE_NAME} 

Rules:

1. Text description can contain a-zA-Z0-9 spaces and "_"
2. Text description need to be followed ":"
3. ":" can be followed with no or one space
4. after ": " string need to start with "${"
5. "VARIABLE_NAME" can contain only A-Z and "_"
6. "VARIABLE_NAME" and line need to finish with "}"

Text can have multiple lines, every line need to follow all 6 rules.

For now i have this regex const regex = new RegExp('[\\w+]:\\$\\{[A-Z]+}$', 'gs'); Just not sure how to handle multiple lines.

Answer 1

The requirements can be matched as follows:

1. → [\w ]+ 2. → : 3. →  ? 4. → \$\{ 5. → [A-Z_]+ 6. → }

Put into a (?: non capturing group (?:\n|$)) + for one or more lines.

^(?:[\w ]+: ?\$\{[A-Z_]+}(?:\n|$))+$

See this demo at regex101 or a JS demo at tio.run (use \r?\n for CRLF support)

Answer 2

You can use

/^[\w ]+:[^\S\r\n]?\${[A-Z_]+}(?:\r?\n[\w ]+:[^\S\r\n]?\${[A-Z_]+})*$/

See the regex demo. Details:

• ^ - start of string
• [\w ]+ - one or more alphanumeric/underscore/space chars
• : - a colon
• [^\S\r\n]? - an optional horizontal whitespace
• \${ - a ${ string
• [A-Z_]+ - one or more uppercase ASCII letters or underscores
• } - a } char
• (?:\r?\n[\w ]+:[^\S\r\n]?\${[A-Z_]+})* - zero or more repetitions of the CRLF or LF line ending sequence followed with the above explained pattern
• $ - end of string.