const regex = /# match a body pattern alone on a line
^\g<body>$
# we'll use (?<name>...){0} to define the pattern \g<name>
# without having to match the pattern at the current position
# a body pattern matches
(?<body>
# a sequence of
(?: [^\[\]{}()\n] # non-delimiters
| \g<parens> # parenthesized pattern
| \g<square_brackets> # bracketed pattern
| \g<curly_braces> # braced pattern
)*
){0}
# a parenthesized pattern matches
(?<parens>
\( # an open paren
\g<body> # a valid body
\) # a close paren
){0}
# a bracketed pattern matches
(?<square_brackets>
\[ # an open square bracket
\g<body> # a valid body
\] # a close square bracket
){0}
# a braced pattern matches
(?<curly_braces>
\{ # an open curly brace
\g<body> # a valid body
\} # a close curly brace
){0}/gm;
// Alternative syntax using RegExp constructor
// const regex = new RegExp('# match a body pattern alone on a line
^\\g<body>$
# we\'ll use (?<name>...){0} to define the pattern \\g<name>
# without having to match the pattern at the current position
# a body pattern matches
(?<body>
# a sequence of
(?: [^\\[\\]{}()\\n] # non-delimiters
| \\g<parens> # parenthesized pattern
| \\g<square_brackets> # bracketed pattern
| \\g<curly_braces> # braced pattern
)*
){0}
# a parenthesized pattern matches
(?<parens>
\\( # an open paren
\\g<body> # a valid body
\\) # a close paren
){0}
# a bracketed pattern matches
(?<square_brackets>
\\[ # an open square bracket
\\g<body> # a valid body
\\] # a close square bracket
){0}
# a braced pattern matches
(?<curly_braces>
\\{ # an open curly brace
\\g<body> # a valid body
\\} # a close curly brace
){0}', 'gm')
const str = `matches:
a plain string
a string containing (matched parens) [matched brackets] and {matched braces}
nested (parens (within) parens)
nested [parens (within) brackets]
()()[({({[]})[({})]})]
non-matches:
(unbalanced parens
([balanced but misordered)]`;
// Reset `lastIndex` if this regex is defined globally
// regex.lastIndex = 0;
let m;
while ((m = regex.exec(str)) !== null) {
// This is necessary to avoid infinite loops with zero-width matches
if (m.index === regex.lastIndex) {
regex.lastIndex++;
}
// The result can be accessed through the `m`-variable.
m.forEach((match, groupIndex) => {
console.log(`Found match, group ${groupIndex}: ${match}`);
});
}
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for JavaScript, please visit: https://developer.mozilla.org/en/docs/Web/JavaScript/Guide/Regular_Expressions