Error: Attempting to access index 1 of an undefined property in an array

var grid = [];
    for (var i = 0;i < 6;i++)
    {
        for (var j = 0; j < 6; j++)
        grid[i] = [];
    }

    //Function to determine the number of bombs nearby
    function check(cx,cy)
    {
        var numb = 0;
        if (grid[cx][cy - 1] == "B") numb++;
        if (grid[cx][cy + 1] == "B") numb++;
        if (grid[cx - 1][cy] == "B") numb++;
        if (grid[cx + 1][cy] == "B") numb++;
        if (grid[cx - 1][cy - 1] == "B") numb++;
        if (grid[cx + 1][cy - 1] == "B") numb++;
        if (grid[cx - 1][cy + 1] == "B") numb++;
        if (grid[cx + 1][cy + 1] == "B") numb++;

        return numb;
    }**

I encountered an error while checking positions with cx +/- 1. I attempted different methods to create the array but was unsuccessful. My goal is to develop a minesweeper game, hence why I am trying to determine how many bombs are near each given index.

javascriptarrays

Answer №1

verify your function

once the check(0,0) is invoked

if (grid[cx][cy - 1] == "B") numb++;

grid[0][0-1]=

what does 0-1 evaluate to?

Answer №2

To avoid accessing elements in an array that do not exist, a helpful approach is to create a function that takes the array and indices as parameters. This function will return true if the value at the specified indices is equal to 'B', otherwise it will return false.

This check can be done using the in operator along with the logical AND operator (logical AND &&). This combination allows for breaking out when encountering false, while continuing on for true before evaluating the value.

function checkB(array, i, j) {
    return i in array && array[i][j] === 'B';
}

// example usage
if (checkB(grid, cx, cy - 1)) numb++;

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