Javascript: Creating an array of arrays

Question

I am trying to create an array of four arrays. Each of this four arrays consists of three numbers, two of them are randomly assigned from a set of numbers.

When I run the following code I don't get an error, but I also don't get a result. What am I missing?
I don't really need the print out in console.log, this is just to check if the array is constructed correctly

var x = -2;
function createEnemy(){
var yArray = [60,145,230]; 
var speedArray = [30,45,55,60]; 
var randY = Math.floor(Math.random() * yArray.length);
var randSpeed = Math.floor(Math.random() * speedArray.length);
var enemy = [yArray[randY], speedArray[randSpeed], x];
}
function printEnemies()
{
var allEnemies = [];
(function setEnemies()
{
allEnemies.push(createEnemy());
allEnemies.push(createEnemy());
allEnemies.push(createEnemy());
allEnemies.push(createEnemy());
}());
for(var j in allEnemies)
{
for(var p in allEnemies[j] )
{
 for(var i = 0; i < allEnemies[j][p].length; i++ )
 {
 console.log(allEnemies[j][p][i]);
 }
 }
}
}
printEnemies();

Answer 1

You forgot to return your enemy :)

function createEnemy() {
 var yArray = [60,145,230]; 
 var speedArray = [30,45,55,60]; 
 var randY = Math.floor(Math.random() * yArray.length);
 var randSpeed = Math.floor(Math.random() * speedArray.length);
 var enemy = [yArray[randY], speedArray[randSpeed], x];
 return enemy;
}

Answer 2

Make sure you return something from createEnemy:

return [yArray[randY], speedArray[randSpeed], x];

Also, you might prefer something like this loop to the nested one you've implemented:

allEnemies.forEach(function (arr) {
 console.log(arr[0], arr[1], arr[2]);
});

Answer 3

Looks like you're missing a 'return enemy' from the createEnemy function and you have an unnecessary tertiary level loop. Here's some modified lines (with some indentation updates for readability).

CODE:

var x = -2;
function createEnemy() {
 var yArray = [60,145,230]; 
 var speedArray = [30,45,55,60]; 
 var randY = Math.floor( Math.random() * yArray.length );
 var randSpeed = Math.floor( Math.random() * speedArray.length );
 var enemy = [yArray[randY], speedArray[randSpeed], x];
 return enemy; // Added a return of the enemy.
}
function printEnemies() {
 var allEnemies = [];
 ( function setEnemies() {
 allEnemies.push(createEnemy());
 allEnemies.push(createEnemy());
 allEnemies.push(createEnemy());
 allEnemies.push(createEnemy());
 }()
 );
 for(var j in allEnemies) {
 for(var p in allEnemies[j] ) {
 console.log (allEnemies [j][p] ); // Removed additional depth of loop
 }
 }
}
printEnemies();