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

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 => some(
  w => char.indexOf(w) > -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) =>
{
  const len = list.length;
  for(const i = 0; i<len; i++)
  {
    if(predicate(list[i]) === true) {
      return true;
    }
  }
  return false;
};

Then just replace some with ssome.

const hasWhitespace = char => some(
  w => char.indexOf(w) > -1,
  whitespaceCharacters
)

For those in Node, use:

const { some } = require('lodash/fp');

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

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

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

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   gt  s includes char          Use character comparison function hasWhiteSpace s      const whitespaceChars           t     n      return Array from s  some char   gt  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

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

[javascript] Check if a string has white space

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