Passing a two Dimensional array in javascript function

Question

I am trying to draw rectangles that represent walls on javascript html canvas. My question here is why doesn't it recognized walls[i].length?

canvas = document.getElementById("myCanvas")
context = canvas.getContext('2d')

var boxSize = 40
var wallsCoordinates = [[3,2][3,3],[3,4]]

function drawWalls(walls) {
context.fillStyle = "grey"
for(var i = 0; i < walls.length; i++) {
    for(var j = 0; j < walls[i].length; j += 2)
        context.fillRect(walls[i][j] * boxSize, walls[i][j + 1] * boxSize,
            boxSize, boxSize)
    }
}

drawWalls(wallsCoordinates)

It does recognize walls[i].length. What exactly is the problem? Note that your code will go 1 element beyond walls[i] because of that j + 1. — Pointy
– Pointy, Commented Oct 4, 2019 at 17:25

Kosonome · Accepted Answer · 2019-10-04 17:27:59Z

1

You forgot a comma in your array.

Change var wallsCoordinates = [[3,2][3,3],[3,4]] to var wallsCoordinates = [[3,2],[3,3],[3,4]].

answered Oct 4, 2019 at 17:27

Kosonome

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3 Comments

Yara Raffoul Over a year ago

Oh god! I forgot the comma at first!

Yara Raffoul Over a year ago

This was such a silly question of me! Only if stack OverFlow allows the author of the question to delete a question under the approval of the people who answered. Thank you tho!

Kosonome Over a year ago

If you think that answer helped you, remember to accept it. ;)

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