Fastest way to check a string contain another substring in JavaScript

Question

I m working with a performance issue on JavaScript  So I just want to ask  what is the fastest way to check whether a string contains another substring  I just need the boolean value   Could you please suggest your idea and sample snippet code

User · Answer

For finding a simple string  using the indexOf   method and using regex is pretty much the same  http   jsperf com substring - so choose which ever one that seems easier to write

User · Answer

I made a jsben ch for you http   jsben ch   aWxtF    seems that indexOf is a bit faster

User · Answer

You have three possibilites   Regular expression    new RegExp  word    test str      or   word  test str    indexOf   str indexOf  word       -1   includes   str includes  word      Regular expressions seem to be faster  at least in Chrome 10   Performance test - short haystack Performance test - long haystack    Update 2011    It cannot be said with certainty which method is faster  The differences between the browsers is enormous  While in Chrome 10 indexOf seems to be faster  in Safari 5  indexOf is clearly slower than any other method  You have to see and try for your self  It depends on your needs  For example a case-insensitive search is way faster with regular expressions   Update 2018  Just to save people from running the tests themselves  here are the current results for most common browsers  the percentages indicate performance increase over the next fastest result  which varies between browsers   Chrome  indexOf   98  faster   lt -- wow Firefox  cached RegExp   18  faster  IE11  cached RegExp  10  faster  Edge  indexOf   18  faster  Safari  cached RegExp  0 4  faster  Note that cached RegExp is  var r   new RegExp  simple    var c   r test str   as opposed to   simple  test str

User · Answer

In ES6  the includes   method is used to determine whether one string may be found within another string  returning true or false as appropriate   var str    To be  or not to be  that is the question     console log str includes  To be              true console log str includes  question           true console log str includes  nonexistent        false   Here is jsperf between   var ret   str includes  one      And   var ret    str indexOf  one       -1     As the result shown in jsperf  it seems both of them perform well

User · Answer

The Fastest   ES6  includes       var string    hello       substring    lo       string includes substring     ES5 and older indexOf       var string    hello       substring    lo       string indexOf substring      -1   http   jsben ch 9cwLJ

User · Answer

It s easy way to use  match   method to string   var re     AND OR MAYBE    var str    IT S MAYBE BETTER WAY TO USE  MATCH   METHOD TO STRING   console log  Do we found something    Boolean str match re       Wish you a nice day  sir

User · Answer

I ve found that using a simple for loop  iterating over all elements in the string and comparing using charAt performs faster than indexOf or Regex  The code and proof is available at JSPerf   ETA  indexOf and charAt both perform similarly terrible on Chrome Mobile according to Browser Scope data listed on jsperf com

User · Answer

Does this work for you   string1 indexOf string2   gt   0   Edit  This may not be faster than a RegExp if the string2 contains repeated patterns   On some browsers  indexOf may be much slower than RegExp   See comments   Edit 2  RegExp may be faster than indexOf when the strings are very long and or contain repeated patterns   See comments and  Felix s answer

[javascript] Fastest way to check a string contain another substring in JavaScript?

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