How to Capture Multiple Groups in JavaScript Regular Expressions?

Access All Captures in JavaScript Regular Expressions

The problem arises when trying to capture multiple groups in a JavaScript regular expression, where only the last capture is retained.

Consider the following example:

"foo bar baz".match(/^(\s*\w+)+$/)

Instead of returning all matches like ["foo", "bar", "baz"], it only returns ["baz"]. This behavior occurs because repeated capturing groups overwrite previous captures.

To resolve this, consider alternative approaches:

• Split on Delimiters: If possible, split the string on a known delimiter instead of using a repeated capturing group.
• Regex with g Flag: Use a regular expression with the g flag to iterate over all matches. Note that this may not be an exact equivalent to repeated capturing groups.
• Multilevel Matching: Perform multiple regex matches to capture specific patterns and then further split or process them.

For instance, to capture a sequence of words enclosed in < > and split them on ;, consider the following example:

var text = "a;b;<c;d;e;f>;g;h;i;<no no no>;j;k;<xx;yy;zz>";

var r = /<(\w+(;\w+)*)>/g;

var match;
while ((match = r.exec(text)) != null) {
  print(match[1].split(";"));
}

This regex splits the captured sequence into individual words.

References:

• [Regular Expressions Information: Repeating vs Capturing Groups](https://www.regular-expressions.info/repeating-a-capturing-group-vs-capturing-a-repeating-group)

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