Array push method behaving strangely javascript

Question

I have a function that takes as an argument an array

[["52", ["41", "43", "61", "63"]], ["54", ["43", "45", "63", "65"]]]

"52" is my coin, and ["41", "43", "61", "63"] are possible movement locations for coin "52". The same applies to "54" and ["43", "45", "63", "65"].

In my case cell.innerHTML == '' for locations "41", "43", "45"

The function is behaving correct until freeLocations.push(freeLocation); where its outputs are

["52", "41"], ["52", "43"], ["54", "43"] and ["54", "45"].

However, allFreePostions.push(freeLocations) is outputting only 3 arrays: ["52", "41"], ["52", "43"] and ["54", "45"]. ["54", "43"] is missing.

strangely if I edit freeLocations.push(freeLocation, j) just for debugging, the missing array shows up in allFreePostions.push(freeLocations).

Am I missing anything here?

function checkFreeLocations(coins){
    let allFreePostions = [];
    let dangerPosition = [];
    for (let i = 0; i < coins.length; i++){
        coin = coins[i][0];
        positions = coins[i][1];
        for (let j = 0; j < positions.length; j++){
            let freeLocations = [];
            let cell = document.getElementById(positions[j]);
            if (cell.innerHTML == ''){
                freeLocation = positions[j];
                freeLocations.push(coin);
                freeLocations.push(freeLocation);
                allFreePostions.push(freeLocations);
            }
        } 
    }
}


checkFreeLocations([["52", ["41", "43", "61", "63"]], ["54", ["43", "45", "63", "65"]]])

I made you a snippet. Please add relevant HTML to make a minimal reproducible example — mplungjan
– mplungjan, Commented Jul 9, 2020 at 8:58

SpudaFett · Accepted Answer · 2020-07-09 10:27:50Z

1

Looks like you have non-unique id's in your HTML which is causing you trouble.

I belive the reason why ["54", "43"] is not showing is because you look to see if an element is empty:

let cell = document.getElementById(positions[j]);
if (cell.innerHTML == ''){
    freeLocation = positions[j];
    freeLocations.push(coin);
    freeLocations.push(freeLocation);
    allFreePostions.push(freeLocations);
}

The case might be that you have already filled that element with ['52', '43'] earlier on. But please add your HTML to make it easier to grasp.

answered Jul 9, 2020 at 10:27

SpudaFett

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1 Comment

Abraham G. Over a year ago

All ids are unique. The reason for double 43 is that both coin 52 and 54 can move to location 43.

Ulett · Accepted Answer · 2020-07-09 09:52:35Z

0

i don't know is this helping or not, but this is how i change all of the data inside coins.

let coins = [
    ["52", 
        ["41", "43", "61", "63"]],
    ["54", 
        ["43", "45", "63", "65"]]
];

console.log(coins);

function checkFreeLocations(coins){
    let allFreePostions = [];
    for (let i = 0; i < coins.length; i++){
        let freeLocations = [];
        freeLocations.push(i);
        
        let freeLocation = [];
        for (let j = 0; j < coins[i][1].length; j++){
            let change = 'X';
            freeLocation.push(change);
        }
        freeLocations.push(freeLocation);
        allFreePostions.push(freeLocations);
    }
    return allFreePostions;
}

console.log(checkFreeLocations(coins));

answered Jul 9, 2020 at 9:52

Ulett

232 bronze badges

2 Comments

Abraham G. Over a year ago

The HTML is a simple setup. it has nonthing. All the coding is done in javascript. I am coding a checker game. I have a table 8x8 filled with 12 black coins and 12 red. before a coin moves it checkes if any of the four diagonal positions are free, and selects the free locations and puts them in an array. for eg coin 52 checks location 41, 43, 61 and 63. As location 61 and 63 are not empty, my possible moves are 52 to 41 and 52 to 43. like wise also with coin 54 locations 43 and 45 are empty, so 54 can move to 43 or 45. so I must have 54 to 43 and 54 to 45. But i am not getting 54 to 43.

Abraham G. Over a year ago

Interstingly, [“54”, “43”] is pushed correctly at freeLocations.push(freeLocation). But in the next line it is missing. In the next line i am only pushing it to other array. [“54”, “43”] is not pushed to allFreePositions.

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