How to count the number of lines of a string in javascript

Question

I want to count the number of lines in a string   i tried to use this stackoverflow answer    lines   str split   r n  r  n     return  lines length    on this string which was originally a buffer     GET   HTTP 1 1  Host  localhost 8888  Connection  keep-alive  Cache-Control  max-age 0  User-Agent  Mozilla 5 0  Macintosh  Intel Mac OS X 10 7 2  AppleWebKit 535 2  KHTML like Gecko  Chrome 15 0 874 121 Safari 535 2  Accept  text html application xhtml xml application xml q 0 9     q 0 8  Accept-Encoding  gzip deflate sdch  Accept-Language  en-US en q 0 8  Accept-Charset  ISO-8859-1 utf-8 q 0 7   q 0 3   and for some reason i got lines  1    any idea how to make it work

User · Answer

To split using a regex use        lines   str split   r n  r  n

User · Answer

Better solution  as str split   n   function creates new array  of strings split by   n  which is heavier than str match   n g   str match   n g  creates array of matching elements only  Which is   n  in our case   var totalLines    str match   n g         length   1

User · Answer

lt script type  text javascript  gt        var multilinestr             line 1         line 2         line 3         line 4         line 5         line 6         totallines   multilinestr split   n    lines   str split   n     console log lines length    lt  script gt    thats works in my case

User · Answer

I made a performance test comparing split with regex  with a string and doing it with a for loop   It seems that the for loop is the fastest   NOTE  this code  as is  is not useful for windows nor macos endline  but should be ok to compare performance   Split with string   split   n   length    Split with regex   split   n   length    Split using for   var length   0  for var i   0  i  lt  sixteen length    i    if sixteen i     s      length      http   jsperf com counting-newlines 2

User · Answer

Using a regular expression you can count the number of lines as   str split   r n  r  n   length   Alternately you can try split method as below   var lines       ptest   val   split   n      alert lines length     working solution  http   jsfiddle net C8CaX

User · Answer

Here is the working sample fiddle  Just remove additional  r n and     from your reg ex

User · Answer

There are three options    Using jQuery  download from jQuery website  - jquery com  var lines       ptest   val   split   n    return lines length    Using Regex  var lines   str split   r n  r  n    return lines length    Or  a recreation of a for each loop  var length   0  for var i   0  i  lt  str length    i       if str i       n             length            return length

User · Answer

I was testing out the speed of the functions  and I found consistently that this solution that I had written was much faster than matching  We check the new length of the string as compared to the previous length  const lines   str length - str replace   n g   quot  quot   length 1    x000D   x000D  let str    Line1 Line2 Line3   console time  LinesTimer   console log  Lines    str length - str replace   n g      length 1   console timeEnd  LinesTimer   x000D   x000D   x000D

User · Answer

Hmm yeah    what you re doing is absolutely wrong  When you say str split   r n  r  n   it will try to find the exact string   r n  r  n   That s where you re wrong  There s no such occurance in the whole string  What you really want is what David Hedlund suggested   lines   str split   r n  r  n    return lines length    The reason is that the split method doesn t convert strings into regular expressions in JavaScript  If you want to use a regexp  use a regexp

User · Answer

Another short  potentially more performant than split  solution is   const lines    str match   n g         length   1

[javascript] How to count the number of lines of a string in javascript

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