There are several methods to check if a substring is contained within a string in Javascript. Here are several methods that should work for you.
The easiest and most compatible method to find a substring within a string in Javascript is to use the match() function with a regular expression.
Find a substring with a regular expression (regex)
This method is compatible with all current versions of Javascript and very simple to use. Here is an example:
var myString = 'This is a javascript string.';
// The / and / set the substrings to regular expressions
var subString1 = /javascript/;
var subString2 = /python/;
myString.match(subString1); // [ 'javascript', index: 10, input: 'This is a javascript string.', groups: undefined ]
myString.match(subString1); // nullCode language: JavaScript (javascript)To make it easy to use the results to test whether the substring exists or not, you can use the !! trick to convert the output to a boolean:
!!myString.match(subString1); // true
!!myString.match(subString1); // falseCode language: JavaScript (javascript)Find a substring with the new includes() method
The includes() string method can also be used to find a substring within another string.
var myString = 'This is a javascript string.';
myString.includes('javascript'); // true
myString.includes('python'); // falseCode language: JavaScript (javascript)