Storing the last encountered bracket type in JavaScript using regular expressions

Question

Storing the last encountered bracket type in JavaScript using regular expressions

My JavaScript code needs to match text that meets the following criteria:

(surrounded by parentheses)
[surrounded by square brackets]
not surrounded by either type of bracket

Given the expression...

none[square](round)(accept]able)[wrong).text

... there should be 4 matches for none, [square], (round), and (accept]able). However, [wrong) should not match as it lacks a closing ].

In my attempted regex found at this link...

([([])[A-Za-z]+[\])]|[^\[()\]]+

...issues arose where (accept], able, and [wrong) matched incorrectly. I prioritize correct matching over partial matches with unbalanced brackets.

To improve my regex, I believe I need to adjust the [\])] expression based on the initial matching group, using ) if starting with ( or ] if starting with [.

I've experimented with conditional expressions. While they work in some regex engines like PCRE and Python, I encountered issues when implementing them in JavaScript (see here).

Can this challenge be tackled solely through a JavaScript regex solution, or will it require separate handling in a complex JavaScript function?

javascript regex conditional-operator

Answer 1

Answer №1

To achieve this, one method is to distinguish between two scenarios (acceptable and non-acceptable) and divide the results into two separate capture groups. This way, when working with the results, you simply need to determine which group is successful:

/(\[[^\]]*\]|\([^)]*\)|[a-z]+)|([\[(][\s\S]*?(?:[\])]|$))/gi

Explaining the pattern further:

(  # acceptable capture group
    \[ [^\]]* \]
  |
    \( [^)]* \)
  |
    [a-z]+
)
|
(  # non-acceptable capture group
    [\[(] [\s\S]*? (?: [\])] | $ ) # unclosed parentheses
)

This pattern allows for variations such as a square bracket within round brackets or vice versa. To restrict this behavior and disallow any other types of brackets between them (square or round), use a more specific pattern like this:

(  # acceptable capture group
    \[ [^()\[\]]* \]
  |
    \( [^()\[\]]* \)
  |
    [a-z]+
)
|
(  # non-acceptable capture group
    [\[(] [\s\S]*? (?: [\])] | $ ) # unclosed parentheses
)

Note that with these patterns, you can adjust how unclosed brackets are handled. By default, the non-acceptable part stops at the first closing bracket encountered or at the end of the string if none is found. However, you have the option to modify this behavior so that an unclosed bracket always terminates at the end of the string by using [\[(][\s\S]*$

Answer 2

To achieve this, one method is to distinguish between two scenarios (acceptable and non-acceptable) and divide the results into two separate capture groups. This way, when working with the results, you simply need to determine which group is successful:

/(\[[^\]]*\]|\([^)]*\)|[a-z]+)|([\[(][\s\S]*?(?:[\])]|$))/gi

Explaining the pattern further:

(  # acceptable capture group
    \[ [^\]]* \]
  |
    \( [^)]* \)
  |
    [a-z]+
)
|
(  # non-acceptable capture group
    [\[(] [\s\S]*? (?: [\])] | $ ) # unclosed parentheses
)

This pattern allows for variations such as a square bracket within round brackets or vice versa. To restrict this behavior and disallow any other types of brackets between them (square or round), use a more specific pattern like this:

(  # acceptable capture group
    \[ [^()\[\]]* \]
  |
    \( [^()\[\]]* \)
  |
    [a-z]+
)
|
(  # non-acceptable capture group
    [\[(] [\s\S]*? (?: [\])] | $ ) # unclosed parentheses
)

Note that with these patterns, you can adjust how unclosed brackets are handled. By default, the non-acceptable part stops at the first closing bracket encountered or at the end of the string if none is found. However, you have the option to modify this behavior so that an unclosed bracket always terminates at the end of the string by using [\[(][\s\S]*$

Answer 3

Answer №2

I'm uncertain if I have captured all potential strings, but perhaps this solution will suffice?

/\[([A-Za-z]*)\]|\(([\]A-Za-z]*)\)/gm

Answer 4

I'm uncertain if I have captured all potential strings, but perhaps this solution will suffice?

/\[([A-Za-z]*)\]|\(([\]A-Za-z]*)\)/gm

Answer 5

Answer №3

Below is a helpful snippet:

/^(\[[^\[]+?\]|\([^\(]+?\)|[^\[\(]+)$/gm

Check out the DEMO

Answer 6

Below is a helpful snippet:

/^(\[[^\[]+?\]|\([^\(]+?\)|[^\[\(]+)$/gm

Check out the DEMO

Answer 7

Answer №4

Here is a solution that should work for you:

\((\w*\s*)\)|\[(\w*)\]|\((\w*\s*|\])*\)|\((\w*\s*|\[)*\)|\[(\w*\s*|\()*\]|\[(\w*\s*|\))*\]|^\b\w*\s*\b

You can see it in action here:

https://regex101.com/r/mV6gD2/2

Answer 8

Here is a solution that should work for you:

\((\w*\s*)\)|\[(\w*)\]|\((\w*\s*|\])*\)|\((\w*\s*|\[)*\)|\[(\w*\s*|\()*\]|\[(\w*\s*|\))*\]|^\b\w*\s*\b

You can see it in action here:

https://regex101.com/r/mV6gD2/2

Storing the last encountered bracket type in JavaScript using regular expressions

Answer №1

Answer №2

Answer №3

Answer №4

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