While we recently checked if a string startsWith or a string endsWith a specific substring, today we will learn how to find out if a string includes another substring.
To do so, we are using the JavaScript function includes().
JavaScript includes() function
We can use the includes() function by calling it on a string and passing a substring to it:
const string =
'The greatest glory in living lies not in never falling, but in rising every time we fall.';
// Check if it includes with `living`
console.log(string.includes('living'));
// true
It is important for the includes() function to know that it is a case-sensitive function. So the following code will fail:
const string =
'The greatest glory in living lies not in never falling, but in rising every time we fall.';
// Check if it includes with `Living`
console.log(string.includes('Living'));
// false
String includes with offset position parameter
As the brothers startsWith() and endsWith(), this has another position parameter. This position is from where it will start to look.
const string =
'The greatest glory in living lies not in never falling, but in rising every time we fall.';
// Check if it includes with `living`
console.log(string.includes('living', 30));
// false
See the code examples in this Codepen
Feel free to play with the code here:
See the Pen Vanilla JavaScript string includes by Chris Bongers (@rebelchris) on CodePen.
Browser Support
This function works well in all modern browsers, including edge!
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