Removing a specific substring from a string in JavaScript

We are given a main string and a substring, our job is to create a function, let's say removeString() that takes in these two arguments and returns a version of the main string which is free of the substring.

Here, we need to remove the separator from a string, for example:

this-is-a-string

Using split() and join() Method

The most common approach is to split the string by the substring and then join the parts back together:

const removeString = (string, separator) => {
    // we split the string and make it free of separator
    const separatedArray = string.split(separator);
    // we join the separatedArray with empty string
    const separatedString = separatedArray.join("");
    return separatedString;
}

const str = removeString('this-is-a-string', '-');
console.log(str);

thisisastring

Using replace() Method

Another approach uses the replace() method with a regular expression to remove all occurrences:

const removeStringReplace = (string, substring) => {
    // Create a global regex to replace all occurrences
    const regex = new RegExp(substring, 'g');
    return string.replace(regex, '');
}

const str2 = removeStringReplace('this-is-a-string', '-');
console.log(str2);

// Example with multiple occurrences
const str3 = removeStringReplace('hello--world--test', '--');
console.log(str3);

thisisastring
helloworldtest

Using replaceAll() Method

For modern JavaScript environments, replaceAll() provides the simplest solution:

const removeStringReplaceAll = (string, substring) => {
    return string.replaceAll(substring, '');
}

const str4 = removeStringReplaceAll('this-is-a-string', '-');
console.log(str4);

// Works with longer substrings too
const str5 = removeStringReplaceAll('remove_this_remove_this_text', '_this_');
console.log(str5);

thisisastring
removeremovetext

Comparison

Conclusion

Use replaceAll() for modern JavaScript environments, or split().join("") for broader browser compatibility. Both methods effectively remove all occurrences of a substring from a string.