Getting "TypeError: Cannot read property 'length' of undefined" while iterating through a 2D array using nested for loops

Tell us what’s happening:
It is a simple question to iterate through a 2D array but it’s not working I don’t know why?
I followed the given instructions but still no use, it’s giving me an error “TypeError: Cannot read property ‘length’ of undefined”. Can someone help?

Your code so far

function multiplyAll(arr) {
var product = 1;
// Only change code below this line

for(var i = 0; i < arr.length; i++)
  for(var j=0; j < arr[i].length; i++)
    product *= arr[i][j];

// Only change code above this line
return product;


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User Agent is: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/80.0.3987.149 Safari/537.36.

Challenge: Nesting For Loops

Link to the challenge:

look really carefully at this line

1 Like

I’m such an obtuse, thank you for helping me.