How do I check for vowels in JavaScript

Question

I m supposed to write a function that takes a character  i e  a string of length 1  and returns true if it is a vowel  false otherwise  I came up with two functions  but don t know which one is better performing and which way I should prefer  The one with RegEx is way simpler but I am unsure whether I should try to avoid using RegEx or not   Without RegEx   function isVowel char      if  char length    1        var vowels   new Array  a    e    i    o    u        var isVowel   false       for  e in vowels          if  vowels e     char            isVowel   true                     return isVowel          With RegEx   function isVowelRegEx char      if  char length    1        return   aeiou   test char

User · Answer

Lots of answers available  speed is irrelevant for such small functions unless you are calling them a few hundred thousand times in a short period of time  For me  a regular expression is best  but keep it in a closure so you don t build it every time   Simple version   function vowelTest s      return     aeiou   i  test s       More efficient version   var vowelTest    function       var re      aeiou   i    return function s        return re test s               Returns true if s is a single vowel  upper or lower case  and false for everything else

User · Answer

I created a simplified version using Array prototype includes    My technique is similar to  Kunle Babatunde    x000D   x000D  const isVowel    char    gt    a    e    i    o    u   includes char   x000D   x000D  console log isVowel  o    isVowel  s     x000D   x000D   x000D

User · Answer

This is a rough RegExp function I would have come up with  it s untested   function isVowel char        return    aeiou    test char toLowerCase         Which means  if  char length    1  amp  amp   aeiou  is contained in char toLowerCase    then return true

User · Answer

function to find vowel const vowel    str   gt       these are vowels we want to check for   const check     a   e   i   o   u        keep track of vowels   var count   0    for let char of str toLowerCase              check if each character in string is in vowel array     if check includes char   count          return count     console log vowel  hello there

User · Answer

I kind of like this method which I think covers all the bases   const matches   str match  aeiou gi   return matches   matches length   0

User · Answer

benchmark  I think you can safely say a for loop is faster   I do admit that a regexp looks cleaner in terms of code  If it s a real bottleneck then use a for loop  otherwise stick with the regular expression for reasons of  elegance   If you want to go for simplicity then just use  function isVowel c        return   a    e    i    o    u   indexOf c toLowerCase        -1

User · Answer

Personally  I would define it this way   function isVowel  chr    return  aeiou  indexOf  chr 0  toLowerCase         -1     You could also use   a   e   i   o   u   and skip the length test  but then you are creating an array each time you call the function   There are ways of mimicking this via closures  but those are a bit obscure to read

User · Answer

function findVowels str      return str match   aeiou  ig      findVowels  abracadabra        aaaaa    Basically it returns all the vowels in a given string

User · Answer

function isVowel char      if  char length    1          var vowels    aeiou       var isVowel   vowels indexOf char   gt   0   true   false       return isVowel          Basically it checks for the index of the character in the string of vowels  If it is a consonant  and not in the string  indexOf will return -1

User · Answer

cycles  arrays  regexp    for what  It can be much quicker     function isVowel char        return char      a     char      e     char      i     char      o     char      u     false

[javascript] How do I check for vowels in JavaScript?

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