RegEx to extract all matches from string using RegExp exec

Question

I m trying to parse the following kind of string    key  val  key2  val2     where there are arbitrary key  val  pairs inside  I want to grab the key name and the value   For those curious I m trying to parse the database format of task warrior    Here is my test string    description  aoeu  uuid  123sth     which is meant to highlight that anything can be in a key or value aside from space  no spaces around the colons  and values are always in double quotes    In node  this is my output    deuteronomy  gatlin      node  gt  var re                        s       g  gt  re exec   description  aoeu  uuid  123sth          description  aoeu  uuid  123sth        uuid      123sth     index  0    input    description  aoeu  uuid  123sth        But description  aoeu  also matches this pattern  How can I get all matches back

User · Answer

My guess is that if there would be edge cases such as extra or missing spaces, this expression with less boundaries might also be an option:

^\s*\[\s*([^\s\r\n:]+)\s*:\s*"([^"]*)"\s*([^\s\r\n:]+)\s*:\s*"([^"]*)"\s*\]\s*$

If you wish to explore/simplify/modify the expression, it's been explained on the top right panel of regex101.com. If you'd like, you can also watch in this link, how it would match against some sample inputs.

Test

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const regex = /^\s*\[\s*([^\s\r\n:]+)\s*:\s*"([^"]*)"\s*([^\s\r\n:]+)\s*:\s*"([^"]*)"\s*\]\s*$/gm;_x000D_
const str = `[description:"aoeu" uuid:"123sth"]_x000D_
[description : "aoeu" uuid: "123sth"]_x000D_
[ description : "aoeu" uuid: "123sth" ]_x000D_
 [ description : "aoeu"   uuid : "123sth" ]_x000D_
 [ description : "aoeu"uuid  : "123sth" ] `;_x000D_
let m;_x000D_
_x000D_
while ((m = regex.exec(str)) !== null) {_x000D_
    // This is necessary to avoid infinite loops with zero-width matches_x000D_
    if (m.index === regex.lastIndex) {_x000D_
        regex.lastIndex++;_x000D_
    }_x000D_
    _x000D_
    // The result can be accessed through the `m`-variable._x000D_
    m.forEach((match, groupIndex) => {_x000D_
        console.log(`Found match, group ${groupIndex}: ${match}`);_x000D_
    });_x000D_
}

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RegEx Circuit

jex.im visualizes regular expressions:

User · Answer

str match  regex g   returns all matches as an array  If  for some mysterious reason  you need the additional information comes with exec  as an alternative to previous answers  you could do it with a recursive function instead of a loop as follows  which also looks cooler     function findMatches regex  str  matches            const res   regex exec str     res  amp  amp  matches push res   amp  amp  findMatches regex  str  matches     return matches       Usage const matches   findMatches  regex g  str   as stated in the comments before  it s important to have g at the end of regex definition to move the pointer forward in each execution

User · Answer

Based on Agus s function  but I prefer return just the match values   var bob     amp gt  bob  amp lt    function matchAll str  regex        var res           var m      if  regex global            while  m   regex exec str                 res push m 1                    else           if  m   regex exec str                 res push m 1                        return res    var Amatch   matchAll bob     amp       g   console log Amatch       yeilds    amp gt    amp lt

User · Answer

I would definatly recommend using the String match   function  and creating a relevant RegEx for it  My example is with a list of strings  which is often necessary when scanning user inputs for keywords and phrases          1  Define keywords     var keywords     apple    orange    banana            2  Create regex  pass  i  for case-insensitive and  g  for global search     regex   new RegExp       keywords join              ig          gt    apple orange banana  gi         3  Match it against any string to get all matches       Test string for ORANGE s or apples were mentioned  match regex         gt    ORANGE    apple     Hope this helps

User · Answer

Iterables are nicer    const matches    text  pattern    gt        Symbol iterator   function            const clone   new RegExp pattern source  pattern flags       let match   null      do         match   clone exec text         if  match            yield match                while  match             Usage in a loop   for  const match of matches  abcdefabcdef    ab g       console log match       Or if you want an array         matches  abcdefabcdef    ab g

User · Answer

str match pattern   if pattern has the global flag g  will return all the matches as an array   For example    x000D   x000D  const str    All of us except  Emran   Raju and  Noman was there   x000D  console log  x000D    str match    w  g  x000D     x000D     Will log    Emran     Raju     Noman   x000D   x000D   x000D

User · Answer

Continue calling re exec s  in a loop to obtain all the matches   var re     s                     g  var s     description  aoeu  uuid  123sth     var m   do       m   re exec s       if  m            console log m 1   m 2            while  m     Try it with this JSFiddle  https   jsfiddle net 7yS2V

User · Answer

This is a solution  var s     description  aoeu  uuid  123sth      var re     s                     g  var m  while  m   re exec s       console log m 1   m 2        This is based on lawnsea s answer  but shorter   Notice that the  g  flag must be set to move the internal pointer forward across invocations

User · Answer

Here is my answer   var str     me nombre es    My name is   Yo puedo  is the right word     var reg              g   var a   str match reg    a   a toString   replace         g      split

User · Answer

Since ES9  there s now a simpler  better way of getting all the matches  together with information about the capture groups  and their index  const string    Mice like to dice rice   const regex     ice gu  for const match of string matchAll regex         console log match            quot mice quot   index  0  input   quot mice like to dice rice quot   groups  undefined       quot dice quot   index  13  input   quot mice like to dice rice quot   groups  undefined       quot rice quot   index  18  input   quot mice like to dice rice quot   groups  undefined   It is currently supported in Chrome  Firefox  Opera  Depending on when you read this  check this link to see its current support

User · Answer

To loop through all matches  you can use the replace function   var re     s                     g  var s     description  aoeu  uuid  123sth      s replace re  function match  g1  g2    console log g1  g2

User · Answer

If you re able to use matchAll here s a trick  Array From has a  selector  parameter so instead of ending up with an array of awkward  match  results you can project it to what you really need  Array from str matchAll regexp   m   gt  m 0     If you have named groups eg       lt firstname gt  a-z  A-Z    g  you could do this  Array from str matchAll regexp   m   gt  m groups firstName

User · Answer

This isn t really going to help with your more complex issue but I m posting this anyway because it is a simple solution for people that aren t doing a global search like you are   I ve simplified the regex in the answer to be clearer  this is not a solution to your exact problem    var re                    var regExResult   re exec  description  aoeu     var purifiedResult   purify regex regExResult       We only want the group matches in the array function purify regex reResult         Removes the Regex specific values and clones the array to prevent mutation   let purifiedArray       reResult         Removes the full match value at position 0   purifiedArray shift          Returns a pure array without mutating the original regex result   return purifiedArray        purifiedResult    description    aoeu     That looks more verbose than it is because of the comments  this is what it looks like without comments  var re                    var regExResult   re exec  description  aoeu     var purifiedResult   purify regex regExResult    function purify regex reResult     let purifiedArray       reResult     purifiedArray shift      return purifiedArray      Note that any groups that do not match will be listed in the array as undefined values   This solution uses the ES6 spread operator to purify the array of regex specific values  You will need to run your code through Babel if you want IE11 support

User · Answer

Here s a one line solution without a while loop     The order is preserved in the resulting list   The potential downsides are    It clones the regex for every match  The result is in a different form than expected solutions  You ll need to process them one more time    let re     s                     g let str     description  aoeu  uuid  123sth      str match re         map e   gt  RegExp re source  re flags  exec e           description  aoeu         description        aoeu       index  0      input   description  aoeu        groups  undefined          uuid  123sth         uuid        123sth       index  0      input    uuid  123sth        groups  undefined

User · Answer

If you have ES9  Meaning if your system  Chrome  Node js  Firefox  etc supports Ecmascript 2019 or later   Use the new yourString matchAll   your-regex     If you don t have ES9 If you have an older system  here s a function for easy copy and pasting function findAll regexPattern  sourceString        let output          let match        make sure the pattern has the global flag     let regexPatternWithGlobal   RegExp regexPattern     new Set  quot g quot  regexPattern flags   join  quot  quot        while  match   regexPatternWithGlobal exec sourceString                get rid of the string copy         delete match input            store the match data         output push match             return output    example usage  console log    findAll  blah g  blah1 blah2         outputs       blah   index  0       blah   index  6

User · Answer

Use this     var all matches   your string match re   console log all matches    It will return an array of all matches   That would work just fine     But remember it won t take groups in account  It will just return the full matches

User · Answer

Here is my function to get the matches    function getAllMatches regex  text        if  regex constructor     RegExp            throw new Error  not RegExp               var res           var match   null       if  regex global            while  match   regex exec text                 res push match                       else           if  match   regex exec text                 res push match                        return res        Example   var regex    abc def ghi g  var res   getAllMatches regex   abcdefghi     res forEach function  item        console log item 0

User · Answer

We are finally beginning to see a built-in matchAll function  see here for the description and compatibility table  It looks like as of May 2020  Chrome  Edge  Firefox  and Node js  12   are supported but not IE  Safari  and Opera  Seems like it was drafted in December 2018 so give it some time to reach all browsers  but I trust it will get there   The built-in matchAll function is nice because it returns an iterable  It also returns capturing groups for every match  So you can do things like     get the letters before and after  o  let matches    stackoverflow  matchAll    w o  w  g    for  match of matches        console log  letter before     match 1        console log  letter after     match 2       arrayOfAllMatches       matches      you can also turn the iterable into an array   It also seem like every match object uses the same format as match    So each object is an array of the match and capturing groups  along with three additional properties index  input  and groups  So it looks like     lt match gt    lt group1 gt    lt group2 gt        index   lt match offset gt   input   lt original string gt   groups   lt named capture groups gt     For more information about matchAll there is also a Google developers page  There are also polyfills shims available

[javascript] RegEx to extract all matches from string using RegExp.exec

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