Example 1: Check String with includes()
// program to check if a string contains a substring
// take input
const str = prompt('Enter a string:');
const checkString = prompt('Enter a string that you want to check:');
// check if string contains a substring
if(str.includes(checkString)) {
console.log(`The string contains ${checkString}`);
} else {
console.log(`The string does not contain ${checkString}`);
}
Output
Enter a string: JavaScript is fun Enter a string that you want to check: fun The string contains fun
The includes() method is used with the if...else statement to check whether a string contains the characters of a specified string.
Note: The includes() method is case-sensitive. Hence, fun and Fun are different.
Example 2: Check String with indexOf()
// program to check if a string contains a substring
// take input
const str = prompt('Enter a string:');
const checkString = prompt('Enter a string that you want to check:');
// check if string contains a substring
if(str.indexOf(checkString) !== -1) {
console.log(`The string contains ${checkString}`);
} else {
console.log(`The string does not contain ${checkString}`);
}
Output
Enter a string: JavaScript is fun Enter a string that you want to check: fun The string contains fun
In the above program, the indexOf() method is used with the if...else statement to check if a string contains a substring.
The indexOf() method searches a string and returns the position of the first occurrence. When a substring cannot be found, it returns -1.
Note: The indexOf() method is case sensitive.
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