In this article, we will see how to remove non-alphanumeric characters from a string in JavaScript. Non-alphanumeric characters are symbols, punctuation, and whitespace. Removing them from a string This task can be useful when you want to clean up user inputs, sanitize strings, or perform various text processing operations.
There are multiple approaches to removing non-alphanumeric characters from a string in JavaScript.
Table of Content
We will explore all the above methods along with their basic implementation with the help of examples.
Approach 1: Using Regular Expressions
Regular expressions offer a concise way to match and remove non-alphanumeric characters. We can use the replace() method with a regular expression to replace all non-alphanumeric characters with an empty string.
Syntax:
function removeNonAlphanumeric(inputString) {
return inputString.replace(/[^a-zA-Z0-9]/g, '');
};
Example: In this example we are using the above-explained approach.
function removeFunction(inputString) {
return inputString.replace(/[^a-zA-Z0-9]/g, '' );
} const originalString = "Hello! This is 123 a test string." ;
const result = removeFunction(originalString);
console.log(result); |
HelloThisis123ateststring
Approach 2: Using a Loop and Character Checking
By iterating through each character in the string and checking if it’s alphanumeric, we can construct the resulting string without non-alphanumeric characters.
Syntax:
for (let i = 0; i < inputString.length; i++) {
const char = inputString[i];
if (/[a-zA-Z0-9]/.test(char)) {
result += char;
}
};
Example: In this example we are using the above-explained approach.
function removeFunction(inputString) {
let result = '' ;
for (let i = 0; i < inputString.length; i++) {
const char = inputString[i];
if (/[a-zA-Z0-9]/.test(char)) {
result += char;
}
}
return result;
} const originalString = "Hello! This is 123 a test string." ;
const result = removeFunction(originalString);
console.log(result); |
HelloThisis123ateststring
Approach 3: Using the replace() Method with a Custom Function
The replace() method can be used with a custom function that checks each character and replaces non-alphanumeric characters.
Syntax:
function removeNonAlphanumeric(inputString) {
return inputString.replace(/./g, char => {
if (/[a-zA-Z0-9]/.test(char)) {
return char;
}
return '';
});
}
Example: In this example we are using the above-explained approach.
function romveFunction(inputString) {
return inputString.replace(/./g, char => {
if (/[a-zA-Z0-9]/.test(char)) {
return char;
}
return '' ;
});
} const originalString = "Hello! This is 123 a test string." ;
const result = romveFunction(originalString);
console.log(result); |
HelloThisis123ateststring