ajDiamond.js

function ajDiamond(input) {
	input = input.toUpperCase();
	var standardInput = ["A","B","C","D","E","F","G","H","I","J"];
	var spacer = " ";
	var index = standardInput.indexOf(input);
	var halfArr = [];
	var tempArr = [];
	var sessionArr = function(index) {
		var arr = [];
		for (var i = 0; i < index; i ++) {
			arr.push(standardInput[i]);
		}
		for (var j = index; j >= 0; j --) {
			arr.push(standardInput[j]);
		}
		return arr;
	};
	if (index === -1) {
		console.log("Invalid input '"+input+"'. Make sure you use a letter in the range A to J.");
	} else {
		console.log("Input: "+input);
		console.log("Output: ");
		console.log("  ");
		for (var i = 0; i < sessionArr(index).length; i ++) {
			if (i < (sessionArr(index).length/2)) {
				for (var j = 0; j < i; j ++) {
					tempArr.push(spacer);
				}
			} else {
				for (var x = 2; x <= i; x ++) {
					halfArr.push(halfArr[i-x]);
				}
			}
			tempArr.push(sessionArr(index)[i]);
			for (var y = i; y < index; y ++) {
				tempArr.push(spacer);
			}
			halfArr.push(tempArr.join(""));
			tempArr.splice(0, tempArr.length);
		}
		for (var z = 0; z < sessionArr(index).length; z++) {
			var originalArr = halfArr[z];
			var reverseArr = halfArr[z].slice(1,halfArr[z].length).split("").reverse().join("");
			var fullArr = reverseArr.concat(originalArr);
			console.log(fullArr);
		}
console.log("   "); // for aesthetic purposes
}
}
// Test cases
ajDiamond("a");
ajDiamond("b");
ajDiamond("c");
ajDiamond("d");
ajDiamond("e");
ajDiamond("f");
ajDiamond("g");
ajDiamond("h");
ajDiamond("i");
ajDiamond("j");