Sometimes, we may want to remove everything after a given character in our JavaScript string.
In this article, we’ll look at how to remove everything after a certain character.
String.prototype.split
We can split a string with the split method.
For instance, we can write:
const url = '/Controller/Action?id=1111&value=2222'
const [path] = url.split('?')
console.log(path)
to get the path string before the question mark with split .
split returns an array of substrings separated by the given character.
So we can destructure the returned array and get the first item.
Therefore, path is: '/Controller/Action’ .
String.prototype.indexOf and String.prototype.substring
The indexOf method lets us get the index of the given character in a string.
We can use it with the substring method to extract the substring from the beginning to the given index returned by indexOf .
For instance, we can write:
const url = '/Controller/Action?id=1111&value=2222'
const path = url.substring(0, url.indexOf('?'));
console.log(path)
We call url.indexOf('?') to get the index of the question mark character.
Then we pass that into substring as the 2nd argument.
0 as the first argument means we get the substring from the first character to the index passed in the 2nd argument.
So path has the same value as before.
Regex Replace
We can also call the string replace method with a regex to remove the part of the string after a given character.
For instance, we can write:
const url = '/Controller/Action?id=1111&value=2222'
const path = url.replace(/\?.*/, '');
console.log(path)
The /\?.*/ regex matches everything from the question to the end of the string.
Since we passed in an empty string as the 2nd argument, all of that will be replaced by an empty string.
replace returns a new string with the replacement applied to it.
So path is the same value as before.
Conclusion
There are several ways we can use to extract the part of the string after the given character with several string methods.
