2D array, i get undefinid ID ?

[Jonforum]

hi why i get error when i delete example DiceSlotBig[3][2 and 3]


i add a conditional if 


if (DiceSlotBig[2]!== null) { 


So, if no found 2d array after de x, y, is suppose to jump the for, and not give me error ?!


the msg error is 


TypeError: Cannot read property 'id' of undefined


Tanks for help guys


 


DiceSlotBig = [
[1206, 571, 'dice-1', 120], // slot 1 [x, y, 'filename', $dataItems[id]] type dice (note: fileName and id are temporly here, need to delete)
[1111, 571, 'dice-2', 121], // slot 2 [x, y, 'filename', $dataItems[id]] type dice
[1013, 571, 'dice-3', 122], // slot 3 [x, y, 'filename', $dataItems[id]] type dice
[917, 571], // slot 4 [x, y, 'filename', $dataItems[id]] type dice ################# this give me error if i delete file name and id like thats ?
[1206, 656, 'dice-5', 124], // slot 5 [x, y, 'filename', $dataItems[id]] type dice
[1111, 656, 'dice-6', 125], // slot 6 [x, y, 'filename', $dataItems[id]] type dice
[1013, 656, 'dice-7', 126], // slot 7 [x, y, 'filename', $dataItems[id]] type dice
[917, 656, 'dice-8', 127], // slot 8 [x, y, 'filename', $dataItems[id]] type dice
[829, 571, 'dice-key-sivler', 128], // slot 9 [x, y, 'filename', $dataItems[id]] type ITEM
[750, 571, 'dice-potion-red', 129], // slot 10 [x, y, 'filename', $dataItems[id]] type ITEM
[829, 656, 'dice-key-gold', 130], // slot 11 [x, y, 'filename', $dataItems[id]] type ITEM
[750, 656, 'dice-potion-blue', 131], // slot 12 [x, y, 'filename', $dataItems[id]] type ITEM
]
var PidDice = 31;
var NBXmargin = 20,
NBYmargin = 20; // marge x y for small Number quantity indicator Dtext
for (i = 0; i <= DiceSlotBig.length - 1; i++) {
console.log(i);
if (DiceSlotBig[2] !== null) {
// check if has item in slot by array ( need filename and dataItems) if null do nothing
//show dice to the X dice to x, y coor slot only if filename exist (fileName will be added in other item menu selector)
//PID start to 31 and max Pid 47
$gameScreen.showPicture(PidDice + i, DiceSlotBig[2], 1, DiceSlotBig[0], DiceSlotBig[1] + 100, 0, 0, 255, 0);
new IAVRA.ANIMATE.Tween($gameScreen.picture(PidDice + i), {
_y: DiceSlotBig[1],
_scaleX: 100,
_scaleY: 100,
_opacity: 255
}).easing(IAVRA.EASING.elastic.out).duration(30).start();
$gameScreen.setDTextPicture('\\OW[5] ' + '\\v[' + $dataItems[DiceSlotBig[3]].id + ']' + ' ', 16); //plugincall dtext
$gameScreen.setFont('GameFont');
$gameScreen.dTextBackColor = 'rgba(0, 0, 0, 0.6)';
$gameScreen.showPicture(PidDice + i + 1, '', 1, DiceSlotBig[0] + NBXmargin, (DiceSlotBig[1] + NBYmargin) + 100, 0, 0, 255, 0);
new IAVRA.ANIMATE.Tween($gameScreen.picture(PidDice + i + 1), {
_y: DiceSlotBig[1] + NBYmargin,
_scaleX: 100,
_scaleY: 100,
_opacity: 255
}).easing(IAVRA.EASING.elastic.out).duration(80).start();
$gameScreen.setPictureCallCommon(PidDice + i, 8, 1); // set able picture to click, bring to CommunEvent 8
PidDice++;
}


}

}


 

 

[taarna23]

Okay, I'm going to work with the strings you have in your arrays, as that is the most identifiable part.


At DiceSlotBig[0][2] you have "dice-1"


At DiceSlotBig[1][2] you have "dice-2"


At DiceSlotBig[2][2] you have "dice-3"


At DiceSlotBig[3][2] you have a problem, because you don't have a 2. DiceSlotBig[3][0] = 917 and DiceSlotBig[3][1] = 571 but DiceSlotBig[3][2] is out of the array bounds.


Basically, the fourth row exists (number 3, as we start counting at 0) but the third column of the fourth row does not.

 

[Jonforum]

Okay, I'm going to work with the strings you have in your arrays, as that is the most identifiable part.


At DiceSlotBig[0][2] you have "dice-1"


At DiceSlotBig[1][2] you have "dice-2"


At DiceSlotBig[2][2] you have "dice-3"


At DiceSlotBig[3][2] you have a problem, because you don't have a 2. DiceSlotBig[3][0] = 917 and DiceSlotBig[3][1] = 571 but DiceSlotBig[3][2] is out of the array bounds.


Basically, the fourth row exists (number 3, as we start counting at 0) but the third column of the fourth row does not.

yes i just fixed, am not understant why 


if (DiceSlotBig[3][2] !== null){}


Give return me true !!! , is suppos  return false.


So i remplace this


by this


if (DiceSlotBig.length > 2) {


And is work

 

[taarna23]

Well, technically speaking, it's NOT null. It's beyond the bounds of the array (JavaScript has some strange returns like this - this is an entertaining reference for some of the weird things JavaScript does: https://www.destroyallsoftware.com/talks/wat ). Checking the length of the array is more reliable anyway, as checking for a null value attempts to index that position of the array and may result in a crash/null reference error.