Determine if a string contains a substring

String.indexOf() returns the index of where the substring starts in the string, or -1 if the substring isn’t found. It’s case-sensitive.

var str = 'I love Cape Cod potato chips.';

// Returns 7
str.indexOf('Cape Cod');

// Returns -1
str.indexOf('cape cod');

Source

https://vanillajstoolkit.com/reference/strings/string-indexof/