Check if a string has white space

Question

I m trying to check if a string has white space  I found this function but it doesn t seem to be working   function hasWhiteSpace s         var reWhiteSpace   new RegExp     s               Check for white space     if  reWhiteSpace test s               alert  Please Check Your Fields For Spaces            return false             return true      By the way  I added quotes to RegExp    Is there something wrong  Is there anything better that I can use  Hopefully JQuery

User · Answer

With additions to the language it is much easier, plus you can take advantage of early return:

// Use includes method on string
function hasWhiteSpace(s) {
  const whitespaceChars = [' ', '\t', '\n'];
  return whitespaceChars.some(char => s.includes(char));
}

// Use character comparison
function hasWhiteSpace(s) {
  const whitespaceChars = [' ', '\t', '\n'];
  return Array.from(s).some(char => whitespaceChars.includes(char));
}

const withSpace = "Hello World!";
const noSpace = "HelloWorld!";

console.log(hasWhiteSpace(withSpace));
console.log(hasWhiteSpace(noSpace));

console.log(hasWhiteSpace2(withSpace));
console.log(hasWhiteSpace2(noSpace));

I did not run performance benchmark but these should be faster than regex but for small text snippets there won't be that much difference anyway.

User · Answer

One simple approach you could take is to compare the length of the original string with that of the string to have whitespaces replaced with nothing  For example   function hasWhiteSpaces string        if  string length    string replace          length   return false      return true

User · Answer

Your regex won t match anything  as it is  You definitely need to remove the quotes -- the     characters are sufficient      s    is checking whether the string is ALL whitespace      matches the start of the string   s  means at least 1  possibly more  spaces    matches the end of the string    Try replacing the regex with   s   and no quotes

User · Answer

A few others have posted answers   There are some obvious problems  like it returns false when the Regex passes  and the   and   operators indicate start end  whereas the question is looking for has  any  whitespace  and not  only contains whitespace  which the regex is checking   Besides that  the issue is just a typo  Change this    var reWhiteSpace   new RegExp  quot    s    quot     To this    var reWhiteSpace   new RegExp  quot   s  quot     When using a regex within RegExp    you must do the two following things     Omit starting and ending   brackets  Double-escape all sequences code  i e     s in place of  s  etc   Full working demo from source code      x000D   x000D    document  ready function e    function hasWhiteSpace s            var reWhiteSpace   new RegExp    s                     Check for white space         if  reWhiteSpace test s                   alert  Please Check Your Fields For Spaces                return  true                          return  false                  whitespace1   html hasWhiteSpace              whitespace2   html hasWhiteSpace  123         x000D   lt script src  https   cdnjs cloudflare com ajax libs jquery 3 3 1 jquery min js  gt  lt  script gt        lt span id  whitespace1  gt  lt  span gt  lt br gt   123    lt span id  whitespace2  gt  lt  span gt  x000D   x000D   x000D

User · Answer

This function checks for other types of whitespace  not just space  tab  carriage return  etc    import some from  lodash fp some  const whitespaceCharacters                   b     t     n     v     f     r                         u0008     u0009     u000A     u000B     u000C     u000D     u0020    u0022     u0027     u005C     u00A0     u2028     u2029     uFEFF   const hasWhitespace   char   gt  some    w   gt  char indexOf w   gt  -1    whitespaceCharacters    console log hasWhitespace  a        a  false console log hasWhitespace           space  true console log hasWhitespace           tab  true console log hasWhitespace   r        carriage return  true   If you don t want to use Lodash  then here is a simple some implementation with 2 s   const ssome    predicate  list    gt      const len   list length    for const i   0  i lt len  i            if predicate list i       true          return true              return false       Then just replace some with ssome   const hasWhitespace   char   gt  some    w   gt  char indexOf w   gt  -1    whitespaceCharacters     For those in Node  use   const   some     require  lodash fp

User · Answer

You can simply use the indexOf method on the input string   function hasWhiteSpace s      return s indexOf       gt   0      Or you can use the test method  on a simple RegEx   function hasWhiteSpace s      return   s g test s       This will also check for other white space characters like Tab

User · Answer

Here is my suggested validation   var isValid   false      Check whether this entered value is numeric  function checkNumeric         var numericVal   document getElementById  txt numeric   value       if isNaN numericVal     numericVal          numericVal    null    numericVal indexOf       gt   0            alert  Please  enter a numeric value             isValid   false        else           isValid   true

[javascript] Check if a string has white space

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