Slice method that one may be able return reverse result

slice.js

function slice(arr) {
    arr = createArrayFromArrayLike(arr);
    return function (start, end, flag) {
    let boundary1 = typeof start === "boolean" || start === undefined || arr.length + start < 0 ? 0 : start < 0 ? arr.length + start : start > arr.length ? arr.length : start;
    let boundary2 = typeof end === "boolean" || end === undefined || end > arr.length ? arr.length : end > 0 ? end : arr.length + end < 0 ? 0 : arr.length + end;
        let inverseFlag = typeof start === "boolean" ? start : typeof end === "boolean" ? end : flag;
        let shift = boundary2 - boundary1;
        if (inverseFlag) {
            let slicedArr = Array(arr.length - shift);
            let key = 0;
            while (key < arr.length) {
                if (key < boundary1) {
                    if (arr.hasOwnProperty(key)) slicedArr[key] = arr[key];
                } else if (key >= boundary2) {
                    if (arr.hasOwnProperty(key)) slicedArr[key - shift] = arr[key];
                } else {
                    key = boundary2;
                    continue;
                }
                key++;
            }
            return slicedArr;
        } else {
            let slicedArr = Array(shift);
            let key = boundary1;
            while (key >= boundary1 && key < boundary2) {
                if (arr.hasOwnProperty(key)) slicedArr[key - boundary1] = arr[key];
                key++;
            }
            return slicedArr;
        }
    };
    function createArrayFromArrayLike(arg) {
        if (Array.isArray(arg)) return arg;
        arg = Object(arg);
        let arr = Array(arg.length ? arg.length : 0);
        let i = -1;
        while (arg.length > ++i) {
            if (arg.hasOwnProperty(i)) arr[i] = arg[i];
        }
        return arr;
    }
}

/// You can simple invoke by next way
let sliceArr = slice(["a", "b", "c", "d", "e"]);
sliceArr(1, 3); /// ["b","c"];
sliceArr(1, 3, true); /// ["a","d","e"]
/// By the way, negative values also works
sliceArr(1, -1); /// ["b","c","d"]
sliceArr(1, -1, true); /// ["a","e"]
/// Also works single digits
sliceArr(3); /// ["d","e"]
sliceArr(3, true); /// ["a","b","c"]
sliceArr(-3); /// ["c","d","e"]
sliceArr(-3, true); /// ["a","b"]
/// Or at all without args, means digits
sliceArr(); /// ["a","b","c","d","e"]
sliceArr(true); /// []