Codefights removeArrayPart(inputArray, l, r)

//sample solution
function removeArrayPart(inputArray, l, r) {
    var testArray = inputArray.slice();
    var testArray2 = inputArray.slice();

    testArray.splice(l); //note that is at L
    return testArray.concat(testArray2.splice(r+1)); //note that is at r + ONE
}