1799     let arrayWithUndefined = ["a", "b", undefined, "d"];  variable
1800     arrayWithUndefined.reverse();
1801     assert_equal(arrayWithUndefined, ['d', undefined, 'b', 'a']);
1825     let arrayWithUndefined = ["a", undefined, "b", "c"];  variable
1826     let shiftedElement4 = arrayWithUndefined.shift();
1828     assert_equal(arrayWithUndefined, [undefined, 'b', 'c']);
1849     let arrayWithUndefined = ["a", undefined, "b", "c"];  variable
1850     let slicedArrayWithUndefined = arrayWithUndefined.slice(1, 3);
1876     let arrayWithUndefined = [1, undefined, 3, 5];  variable
1877     let isSomeUndefined = arrayWithUndefined.some(num => num === undefined);
1899     let arrayWithUndefined = [1, undefined, 3, 5];  variable
1900     arrayWithUndefined.sort();
1901     assert_equal(arrayWithUndefined, [1,3,5,undefined]);
1929     let arrayWithUndefined = [1, undefined, 3, 5];  variable
1930     let removedElements4 = arrayWithUndefined.splice(1, 2);
1932     assert_equal(arrayWithUndefined, [1, 5]);
1975     let arrayWithUndefined = [1, 2, undefined];  variable
1976     let newLength4 = arrayWithUndefined.unshift("x");
1978     assert_equal(arrayWithUndefined, ['x', 1, 2, undefined]);
2006     let arrayWithUndefined = ["a", "b", undefined, "d"];  variable
2007     assert_equal(arrayWithUndefined.toReversed(), ['d', undefined, 'b', 'a']);
2020     let arrayWithUndefined = [1, undefined, 3, 5];  variable
2021     assert_equal(arrayWithUndefined.toSorted(), [1,3,5,undefined]);
2043     let arrayWithUndefined = [1, undefined, 3, 5];  variable
2044     let removedElements4 = arrayWithUndefined.toSpliced(1, 2);
2046     assert_equal(arrayWithUndefined, [1,undefined,3,5]);