Javascript remove all nonalphanumeric characters


Introduction


In this article, we will show you how to remove all non-alphanumeric characters from a string in JavaScript.

We will use the regular expression method to remove all non-alphanumeric characters from a string. A regular expression is an object that describes a pattern of characters.

For instance, the regular expression \s matches any white space character, including space, tab, form feed, and new line.

The regular expression /\s+/ matches one or more white space characters.

The replace() method searches a string for a specified value and replaces it with another value.

let str = "abcdef!@#$%^&*()_+";

console.log(str.replace(/\W/g, '')); // "abcdef"</p><br /><h2>Use a Regular Expression</h2><br /><p> To remove all nonalphanumeric characters from a string, you can use the `replace()` method with a regular expression. The regular expression will remove all characters that are not alphanumeric or a space. This includes punctuation, symbols, and whitespace. The `replace()` method will return a new string with the replaced character.</p><br /><h3>Use the replace() function</h3><br /><p>

You can use the replace() function in JavaScript to remove all non-alphanumeric characters from a string. The function takes two arguments: the first is the regular expression that will be used to identify the characters to be removed, and the second is an empty string that will replace any character that matches the regular expression. For example, to remove all non-alphanumeric characters from a string, you could use the following code:

var myString = "This is a test string!";
var newString = myString.replace(/[^a-z0-9]/gi,'');
// newString will now be "Thisisateststring"</p><br /><h3>Use a RegExp object</h3><br /><p>

Regular expressions are patterns used to match character combinations in strings. In JavaScript, regular expressions are also objects. These patterns are used with the exec and test methods of RegExp, and with the match, replace, search, and split methods of String. This chapter describes JavaScript regular expressions.

JavaScript regular expressions have four optional flags that allow you to control the way a pattern is matched against a string:

g – global match
i – ignore case
m – multiline match
y – sticky match
The flags can be used independently or together in any order. For example, /ab/gi would be the same as /(?:ab)/gi. The only exception is the y flag, which cannot be used with the g flag.

Use the String.prototype.match() method

The String.prototype.match() method is used to retrieve the matches when matching a string against a regular expression.

Use the String.prototype.replace() method


You can use the replace() method to replace all non-alphanumeric characters with an empty string.

For instance, given the following string:

var str = “Hello!+*”;
You can remove all non-alphanumeric characters from it like so:

str.replace(/[^a-z0-9]/gi, ”); // “Hello”

Conclusion

return str.replace(/[^a-zA-Z0-9]/g, “”);


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