How to Remove Character from String in JavaScript

JavaScript developers use strings to store texts of information. Often they need to replace or remove one or more characters from the string using JavaScript. In this article, we will learn how to remove character from string in JavaScript.

How to Remove Character from String in JavaScript

Let us say you have the following string ‘good morning’. Here are the different ways to remove character ‘o’ from string in JavaScript.

1. Using Replace()

Every JavaScript string supports replace() function that basically allows you to replace the first occurrence of a character in string. Here is its syntax.

string.replace(old_character,new_character);

To remove a character from a string, you can simply replace it with empty character ”. Here is an example to replace the first occurrence of letter ‘o’ in ‘good morning’.

var a = 'good morning';
res = a.replace('o','');
console.log(res); // output is 'god morning'

You can use replace function with string variables as well as literal strings. Here is an example using literal strings.

res='good morning'.replace('o','');
console.log(res); // output is 'god morning'

If you want to replace all occurrences of a character then you need to specify a regular expression instead of a literal character by enclosing with within /…/g

var a = 'good morning';
var result=a.replace(/o/g,'');
console.log(result); // output is gd mrning

2. Using ReplaceAll()

You can also use replaceAll() function to replace all occurrences of a character or substring in a string. Here is its syntax.

string.replaceAll(old_substring, new_substring)

Here is the example to replace all occurrences of character ‘o’ in string.

var a = 'good morning';
var result=a.replaceAll('o','');
console.log(result); // output is gd mrning

If you want to replace only the first occurrence of the character then you need to pick a substring that contains the first occurrence of the character, and replace it with the same expression without the first character. Here is an example to replace only the first occurrence of the character ‘o’.

var a = 'good morning';
var result=a.replaceAll('ood','od');
console.log(result); // output is god morning

3. Using Split & Join

If there is only one occurrence of a character in string, then you can split the string into substrings using that character as a delimiter, and join the substrings back using empty character ”. If there are multiple occurrences of the character, then all occurrences will be replaced. Here is an example to demonstrate it.

var a = 'good morning';
var result=a.split('o').join('');
console.log(result);

In the above code, we have used split() function to split the string using ‘o’ as delimiter. We have then called join() function on split function’s result, to concatenate individual substrings into a string. During joining, we have used empty character ”.

4. Using Filter() function

Every JavaScript string can be treated as an array. Filter() is a useful function that allows you to filter out all array items that pass a certain test. We can use it to get all characters of a string, except the ones to be removed.

Alternatively, you can filter out the characters to be removed from the array, then join back the remaining array parts back into a string, using join() function. Here is an example to replace all occurrences of letter ‘o’ in ‘good morning’.

var a = 'good morning';
let c = 'o';
let res = Array.from(a)
    .filter(char => char !== c)
    .join('');
console.log(res); // output is gd morning

5. Using for loop

There are some very specific use cases that cannot be easily solved by any of the above solutions. In such cases, it is best to use the good old fashioned for loop to iterate through the string characters one by one and replace character as per your requirement. Let us say you want to replace the 2nd occurrence of letter ‘o’ in ‘good morning’. In such cases, it is easy to just loop through the string and replace the character of your choice.

var a = 'good morning';
var b = 'o';
var result='';
var count=0;
for (let i = 0; i < a.length; i++) {
    if (a[i]==b) {
        count++;
        if(count==2){
            continue;
        }
        else{
            result += a[i];
        }
    }else{
        result += a[i];
    }
}
console.log(result);

In the above code, we define a result string to store our result, and we loop through our main string. In each iteration, we check if the character is ‘o’. If so, we increment the count variable. If count=2, then we skip the character, else we append it to result string.

As you can see, although this method is a little longer, it allows you to easily handle complex use cases as per your requirement.

Conclusion

In this article, we have learnt many different ways to remove a character from string. If you want to replace the first occurrence of a string, then you can use replace() function. If you want to replace all occurrences of a character, then either use regular expression in replace() function, or use replaceAll() function. However, if you have a complicated use case such as replacing the 2nd or 3rd occurrence of a character, or removing multiple non-continuous characters then it is better to simply loop through the string, inspect each character and remove/replace it as per your requirement.

Also read:

How To Replace Occurrences of Substring in JavaScript
How to Check Whether String Contains Substring in JavaScript
How to Remove Empty Elements from JavaScript Array