In this question, you need to build an exact replica of the
indexOf method provided by Array.
indexOf() method returns the first index at which a given element can be found in the array, or -1 if it is not present.
indexOf(searchElement) indexOf(searchElement, fromIndex)
Element to locate in the array.
fromIndex (Optional) -
The index to start the search at. If the index is greater than or equal to the array's length, -1 is returned, which means the array will not be searched. If the provided index value is a negative number, it is taken as the offset from the end of the array. Note: if the provided index is negative, the array is still searched from front to back. If the provided index is 0, then the whole array will be searched. Default: 0 (entire array is searched).
The first index of the element in the array; -1 if not found.
indexOf() compares searchElement to elements of the Array using strict equality (the same method used by the === or triple-equals operator).
var array = [2, 9, 9]; array.indexOf(2); // 0 array.indexOf(7); // -1 array.indexOf(9, 2); // 2 array.indexOf(2, -1); // -1 array.indexOf(2, -3); // 0