How to check if a string array contains one string in JavaScript

Question

I have a string array and one string  I d like to test this string against the array values and apply a condition the result - if the array contains the string do  A   else do  B    How can I do that

User · Answer

You can use the indexOfmethod and  extend  the Array class with the method contains like this   Array prototype contains   function element       return this indexOf element   gt  -1       with the following results     A    B    C   contains  A   equals true     A    B    C   contains  D   equals false

User · Answer

This will do it for you   function inArray needle  haystack        var length   haystack length      for var i   0  i  lt  length  i              if haystack i     needle              return true            return false      I found it in Stack Overflow question JavaScript equivalent of PHP s in array

User · Answer

Create this function prototype   Array prototype contains   function   needle        for  i in this          if  this i     needle  return true          return false      and then you can use following code to search in array x  if  x contains  searchedString             do a   else            do b

User · Answer

var stringArray     String1    String2    String3     return  stringArray indexOf searchStr   gt  -1

User · Answer

There is an indexOf method that all arrays have  except Internet Explorer 8 and below  that will return the index of an element in the array  or -1 if it s not in the array   if  yourArray indexOf  someString    gt  -1          In the array    else         Not in the array     If you need to support old IE browsers  you can polyfill this method using the code in the MDN article

[javascript] How to check if a string array contains one string in JavaScript?

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