Sometimes, we want to check if a string is entirely made of the same substring with JavaScript.
In this article, we’ll look at how to check if a string is entirely made of the same substring with JavaScript.
How to check if a string is entirely made of the same substring with JavaScript?
To check if a string is entirely made of the same substring with JavaScript, we can use the indexOf method with a string that concatenated with itself.
For instance, we write
const check = (str) => {
return (str + str).indexOf(str, 1) !== str.length;
};
to check if the start index of str in str + str when searching from index 1 isn’t str.length.
If this is true, then str isn’t entirely made of the same substring as itself.
Conclusion
To check if a string is entirely made of the same substring with JavaScript, we can use the indexOf method with a string that concatenated with itself.
