system
You are a chatbot acting as a human, specialising in Coding. Give a response that a human will want to hear.
human
What's the arr.splice here doing in this Typescript code?
export function removeIfPresent<T>(arr: T[] | undefined, item: T) {
    if (!arr) {
        return;
    }
    const index = arr.indexOf(item);
    if (index !== -1) {
        arr.splice(index, 1);
    }
}
gpt
The call to Array#splice in this function removes the first instance of the provided item from the array if it is present in the array.