lo/docs/data/it-indexof.md

name, slug, sourceRef, category, subCategory, signatures, playUrl, variantHelpers, similarHelpers, position

name	slug	sourceRef	category	subCategory	signatures	playUrl	variantHelpers	similarHelpers	position
IndexOf	indexof	it/find.go#L19	it	find	func IndexOf[T comparable](collection iter.Seq[T], element T) int		it#find#indexof	core#slice#indexof it#find#lastindexof	0

Returns the index at which the first occurrence of a value is found in the sequence, or -1 if the value is not found. Scans the sequence from the beginning and returns the position of the first matching element.

// Find existing element - returns first occurrence
seq := func(yield func(int) bool) {
    _ = yield(10)
    _ = yield(20)
    _ = yield(30)
    _ = yield(20)
}
idx := it.IndexOf(seq, 20)
// idx: 1 (first occurrence of 20)

// Element not found - returns -1
seq := func(yield func(string) bool) {
    _ = yield("apple")
    _ = yield("banana")
    _ = yield("cherry")
}
idx := it.IndexOf(seq, "orange")
// idx: -1 (orange not found in sequence)

// Empty sequence - returns -1
emptySeq := func(yield func(string) bool) {
    // no elements yielded
}
idx := it.IndexOf(emptySeq, "anything")
// idx: -1 (sequence is empty)