indexOfOrThrow

indexOfOrThrow(target, source)

Returns the index of the first occurrence of source string in target string, or throws an error if not found.

data-first

indexOfOrThrow("hello world", "world"); // 6
indexOfOrThrow("hello world", "foo"); // throws FnError

data-last

pipe("hello world", indexOfOrThrow("world")); // 6
pipe("hello world", indexOfOrThrow("foo")); // throws FnError