CODEWITHSUNDEEP
javascriptregex
Allen Marshall
Allen Marshall

Reputation: 391

How to use Nested RegEx

I'm trying to convert this:
\/\*[^*\/]*(?:(?!\/\*|\*\/)[*\/][^*\/]*)*\*\/g
This is a nested Regex that works perfectly

/* one */
Stuff one
/* two /* three */ two */
Stuff two
/* four */



Into something like this:
a: {[^\}]*(?:(?!a: {|\})[\}][^\}]*)*\}g (Does not work properly)
I have been trying to get this to work for days now… no luck.

a: { one }
Stuff one
a: { two a: { three } two }
Stuff two
a: { four }


How it's suppose to work

source = "/* one */ Stuff one /* two  /* three */  two */ Stuff two /* four */"

regex = /\/\*[^*\/]*(?:(?!\/\*|\*\/)[*\/][^*\/]*)*\*\//g

results = source.match(regex)


$("body").append("<pre>" + JSON.stringify(results, null, 2) + "</pre>")
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>

What I've done

source = "a: { one } Stuff one a: { two  a: { three }  two } Stuff two a: { four }"

regex = /a: {[^\}]*(?:(?!a: {|\})[\}][^\}]*)*\}/g

results = source.match(regex)


$("body").append("<pre>" + JSON.stringify(results, null, 2) + "</pre>")
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>

What I've done… is showing this:
a: { one }
Stuff one
a: { two a: { three } two }
Stuff two
a: { four }


But it should be this
a: { one }
Stuff one
a: { two a: { three } two }
Stuff two
a: { four }

Upvotes: 0

Views: 277

Answers (1)

Monwell Partee
Monwell Partee

Reputation: 718

For capturing the deepest nest

use /\ba: {(?:(?!\ba: {.*}).)*?}/g

source = "a: { one } Stuff one a: { one a: { two a: { three } two} one } a: { one a: { two } one } fdsf dsae a: { one } Stuff two Stuff three a: { one a: { two a: { three a: { four } three} two} one } a: { one }"

regex = /\ba: {(?:(?!\ba: {.*}).)*?}/g
results = source.match(regex)


$("body").append("<pre>" + JSON.stringify(results, null, 2) + "</pre>")
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>



For capturing entire nest

use /\ba: {.*?(?:(?!\ba: {.*}).)*}/g

source = "a: { one } Stuff one a: { one a: { two a: { three } two} one } a: { one a: { two } one } fdsf dsae a: { one } Stuff two Stuff three a: { one a: { two a: { three a: { four } three} two} one } a: { one }"

regex = /\ba: {.*?(?:(?!\ba: {.*}).)*}/g
results = source.match(regex)


$("body").append("<pre>" + JSON.stringify(results, null, 2) + "</pre>")
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>



Has to be considered a nest

use /\ba: {[^}]*\ba: .*?(?:(?!\ba: {.*}).)*}/g

source = "a: { one } Stuff one a: { one a: { two a: { three } two} one } a: { one a: { two } one } fdsf dsae a: { one } Stuff two Stuff three a: { one a: { two a: { three a: { four } three} two} one } a: { one }"

regex = /\ba: {[^}]*\ba: .*?(?:(?!\ba: {.*}).)*}/g
results = source.match(regex)


$("body").append("<pre>" + JSON.stringify(results, null, 2) + "</pre>")
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>



Organize both possible nest and true nests

use /\ba: {\s?[^}]*\ba: {.*?(?:(?!\ba: {.*}).)*}|(\ba: {.*?(?:(?!\ba: {.*}).)*})/g

source = "a: { one } Stuff one a: { one a: { two a: { three } two} one } a: { one a: { two } one } fdsf dsae a: { one } Stuff two Stuff three a: { one a: { two a: { three a: { four} three} two} one } a: { one }"

regex = /\ba: {\s?[^}]*\ba: {.*?(?:(?!\ba: {.*}).)*}|(\ba: {.*?(?:(?!\ba: {.*}).)*})/g
results = source.match(regex)

for (let i = 0; i < results.length; i++) {
  breakdown = regex.exec(source)

  if (breakdown[1]) {
    $(".box1").append(breakdown[1] + '<br>')
  } else {
    $(".box2").append(breakdown[0] + '<br>')
  }

}
.boxes {
  padding: 0px 30px;
  position: absolute;
}

.box2 {
  right: 0px;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div class="boxes box1"></div>
<div class="boxes box2"></div>

Upvotes: 2

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