Return positions of a regex match in Javascript

Question

Is there a way to retrieve the  starting  character positions inside a string of the results of a regex match   in Javascript

User · Accepted Answer

Here s what I came up with    x000D   x000D     Finds starting and ending positions of quoted text x000D     in double or single quotes with escape char support like       x000D  var str    this is a   quoted   string as you can  read    x000D   x000D  var patt                                        igm  x000D   x000D  while  match   patt exec str     x000D    console log match index         patt lastIndex   x000D    x000D   x000D   x000D

User · Answer

function trimRegex str  regex       return str substr str match regex  index  split     reverse   join     substr str match regex  index  split     reverse   join         let test      ab  cd     trimRegex test           console log test     output  ab  cd   or  function trimChar str  trim  req       let regex   new RegExp      trim           return str substr str match regex  index  split     reverse   join     substr str match regex  index  split     reverse   join         let test      ab  cd     trimChar test        console log test     output  ab  cd

User · Answer

x000D   x000D  var str    my string here    var index   str match  hre   index   alert index       lt - 10 x000D   x000D   x000D

User · Answer

You can use the search method of the String object  This will only work for the first match  but will otherwise do what you describe  For example    How are you   search  are       4

User · Answer

var str    The rain in SPAIN stays mainly in the plain    function searchIndex str  searchValue  isCaseSensitive      var modifiers   isCaseSensitive    gi     g     var regExpValue   new RegExp searchValue  modifiers     var matches         var startIndex   0    var arr   str match regExpValue         forEach call arr  function element        startIndex   str indexOf element  startIndex       matches push startIndex              return matches     console log searchIndex str   ain   true

User · Answer

From developer mozilla org docs on the String  match   method      The returned Array has an extra input property  which contains the   original string that was parsed  In addition  it has an index   property  which represents the zero-based index of the match in the   string    When dealing with a non-global regex  i e   no g flag on your regex   the value returned by  match   has an index property   all you have to do is access it   var index   str match  regex   index    Here is an example showing it working as well    x000D   x000D  var str    my string here   x000D   x000D  var index   str match  here   index  x000D   x000D  alert index       lt - 10 x000D   x000D   x000D    I have successfully tested this all the way back to IE5

User · Answer

In modern browsers  you can accomplish this with string matchAll    The benefit to this approach vs RegExp exec   is that it does not rely on the regex being stateful  as in  Gumbo s answer   x000D   x000D  let regexp    bar g  let str    foobarfoobar    let matches       str matchAll regexp    matches forEach  match    gt        console log  match found at     match index       x000D   x000D   x000D

User · Answer

This member fn returns an array of 0-based positions  if any  of the input word inside the String object  String prototype matching positions   function   word   case sensitive   whole words   multiline          besides   word  param  others are flags  0 1       var  match pattern    g    case sensitive  i        multiline  m           var  bound    whole words      b            var  re   new RegExp   bound  word  bound   match pattern       var  pos        chunk   index   0       while  true               chunk    re exec  this           if    chunk    null   break          pos push   chunk  index              re lastIndex    chunk  index   1            return  pos       Now try  var  sentence    What do doers want   What do doers need      var  word    do    console log   sentence matching positions   word  1  0  0      console log   sentence matching positions   word  1  1  0        You can also input regular expressions   var  second    z 2 2z-1    console log   second matching positions    0-9  z    0  0  0        Here one gets the position index of linear term

User · Answer

Here is a cool feature I discovered recently  I tried this on the console and it seems to work   var text    border-bottom-left-radius    var newText   text replace  - g function match  index       return       index              Which returned   border 6 bottom 13 left 18 radius   So this seems to be what you are looking for

User · Answer

exec returns an object with a index property    x000D   x000D  var match    bar  exec  foobar    x000D  if  match    x000D      console log  match found at     match index   x000D    x000D   x000D   x000D    And for multiple matches    x000D   x000D  var re    bar g  x000D      str    foobarfoobar   x000D  while   match   re exec str      null    x000D      console log  match found at     match index   x000D    x000D   x000D   x000D

[javascript] Return positions of a regex match() in Javascript?

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