https://repl.it/C1T0/105 created by sethopia

Push and Pop (2.6) Extra Problems.js

/*
	PUSH POP
	
	Write your own versions of Push and Pop
	
	Push takes two arguments, an array, and a value to add to that array. The function should return the array modified to include the new value.

    push([8,2,3,4], 5)
    // -> [8,2,3,4,5] 
    
    Pop is a function that manipulates an array. You can think of it like the opposite of push. It takes the last thing off the array and returns it

    var arr = [1,2,3,4];
    pop(arr)
    // -> 4

	While it returns the last thing in the array, it also removes it from the array. If you inspect `arr` after calling pop, it will be `[1,2,3]`.
*/

function push(arr, val) {
	var newArr = arr.slice();
	newArr[arr.length] = val;
	return newArr;
}


/*

	NOTE: The suggested way to write the function (see below) is to use splice method, which modifies the array it's called
	on. So could use returnVal = arr.splice(arr.length - 1, 1). returnVal would be an array, so we'd need to return
	returnVal[0].
	
	Here's another set of suggested solutions:
	
	
	function push(arr, val) {
	  arr[arr.length] = val;
	  return arr;
	}
	
	function pop(arr) {
	  var val = arr[arr.length-1];
	  arr.length--;						// Here they're shortening the array with length property instead of using delete.
	  return val;
	}
	

	
*/


function pop(arr) {
	var returnVal = arr[arr.length - 1];
	delete(arr[arr.length - 1]); // why does this delete the last array element in global scope
	arr = []; // when this does not delete any elements in global scope?
	return returnVal;
}

var testArr = [8,2,3,4];
var modArr = push(testArr,5);
console.log("push values below");
console.log(testArr);
console.log(modArr);

var testArr2 = [1,2,3,4];
var myReturnVal = pop(testArr2);
console.log("\npop values below");
console.log(myReturnVal);
console.log(testArr2);

Push and Pop (2.6) Extra Problems_console_dump.txt

Native Browser JavaScript

push values below
[ 8, 2, 3, 4 ]
[ 8, 2, 3, 4, 5 ]

pop values below
4
[ 1, 2, 3 ]