PHP

check if string contains substring

Like this:

if (str.indexOf("Yes") >= 0)
...or you can use the tilde operator:

if (~str.indexOf("Yes"))
This works because indexOf() returns -1 if the string wasn't found at all.

Note that this is case-sensitive.
If you want a case-insensitive search, you can write

if (str.toLowerCase().indexOf("yes") >= 0)
Or:

if (/yes/i.test(str))

str_contains — Determine if a string contains a given substring

<?php
if (str_contains('abc', '')) {
    echo "Checking the existence of the empty string will always return true";
}
?>

string contains a substring

const string = "foo";
const substring = "oo";

console.log(string.includes(substring)); // true