How do you ignore case-sensitive strings?

To do a case insensitive check if an array contains a string in JavaScript:

The equalsIgnoreCase() method compares two strings, ignoring lower case and upper case differences. This method returns true if the strings are equal, and false if not. Tip: Use the compareToIgnoreCase() method to compare two strings lexicographically, ignoring case differences.

To do case insensitive search, you can use regular expressions and the String#match() function , or you can convert both the string and substring to lower case using the String#toLowerCase() function.

The indexOf() method returns the index number where the target string is first found or -1 if the target is not found. Like equals(), the indexOf() method is case-sensitive , so uppercase and lowercase chars are considered to be different.