[javascript] Remove all special characters except space from a string using JavaScript

I want to remove all special characters except space from a string using JavaScript.

For example, abc's test#s should output as abcs tests.

The first solution does not work for any UTF-8 alphabet. (It will cut text such as ??????). I have managed to create a function which does not use RegExp and use good UTF-8 support in the JavaScript engine. The idea is simple if a symbol is equal in uppercase and lowercase it is a special character. The only exception is made for whitespace.

function removeSpecials(str) {
    var lower = str.toLowerCase();
    var upper = str.toUpperCase();

    var res = "";
    for(var i=0; i<lower.length; ++i) {
        if(lower[i] != upper[i] || lower[i].trim() === '')
            res += str[i];
    }
    return res;
}

Update: Please note, that this solution works only for languages where there are small and capital letters. In languages like Chinese, this won't work.

Update 2: I came to the original solution when I was working on a fuzzy search. If you also trying to remove special characters to implement search functionality, there is a better approach. Use any transliteration library which will produce you string only from Latin characters and then the simple Regexp will do all magic of removing special characters. (This will work for Chinese also and you also will receive side benefits by making Tromsø == Tromso).

I don't know JavaScript, but isn't it possible using regex?

Something like [^\w\d\s] will match anything but digits, characters and whitespaces. It would be just a question to find the syntax in JavaScript.

I tried Seagul's very creative solution, but found it treated numbers also as special characters, which did not suit my needs. So here is my (failsafe) tweak of Seagul's solution...

//return true if char is a number
function isNumber (text) {
  if(text) {
    var reg = new RegExp('[0-9]+$');
    return reg.test(text);
  }
  return false;
}

function removeSpecial (text) {
  if(text) {
    var lower = text.toLowerCase();
    var upper = text.toUpperCase();
    var result = "";
    for(var i=0; i<lower.length; ++i) {
      if(isNumber(text[i]) || (lower[i] != upper[i]) || (lower[i].trim() === '')) {
        result += text[i];
      }
    }
    return result;
  }
  return '';
}

Whose special characters you want to remove from a string, prepare a list of them and then user javascript replace function to remove all special characters.

var str = 'abc'de#;:sfjkewr47239847duifyh';
alert(str.replace("'","").replace("#","").replace(";","").replace(":",""));

or you can run loop for a whole string and compare single single character with the ASCII code and regenerate a new string.

Try this:

const strippedString = htmlString.replace(/(<([^>]+)>)/gi, "");
console.log(strippedString);

dot (.) may not be considered special. I have added an OR condition to Mozfet's & Seagull's answer:

function isNumber (text) {
      reg = new RegExp('[0-9]+$');
      if(text) {
        return reg.test(text);
      }
      return false;
    }

function removeSpecial (text) {
  if(text) {
    var lower = text.toLowerCase();
    var upper = text.toUpperCase();
    var result = "";
    for(var i=0; i<lower.length; ++i) {
      if(isNumber(text[i]) || (lower[i] != upper[i]) || (lower[i].trim() === '') || (lower[i].trim() === '.')) {
        result += text[i];
      }
    }
    return result;
  }
  return '';
}

You can do it specifying the characters you want to remove:

string = string.replace(/[&\/\\#,+()$~%.'":*?<>{}]/g, '');

Alternatively, to change all characters except numbers and letters, try:

string = string.replace(/[^a-zA-Z0-9]/g, '');

search all not (word characters || space):

str.replace(/[^\w ]/, '')

Try to use this one

var result= stringToReplace.replace(/[^\w\s]/g, '')

[^] is for negation, \w for [a-zA-Z0-9_] word characters and \s for space, /[]/g for global