method Array.lastIndexOf Private Array.lastIndexOf(searchElement: T,fromIndex?: number,): number Returns the index of the last occurrence of a specified value in an array, or -1 if it is not present. Parameters searchElement: T The value to locate in the array. optional fromIndex: number The array index at which to begin searching backward. If fromIndex is omitted, the search starts at the last index in the array. Return Type number