Can someone please explain what this error means!

Question

TypeError: Cannot read properties of undefined (reading 'length')

From this code:

function largestOfFour(arr) {

var maxx = [0,0,0,0];

for(var i = 0; i < arr.length; i++) {

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

if(arr[i][j] > maxx[i]) {
maxx[i] = arr[i][j];
}
}
}

return maxx;
}

largestOfFour([[4, 5, 1, 3], [13, 27, 18, 26], [32, 35, 37, 39], [1000, 1001, 857, 1]]);

Answer 1

I would recommend you to give
One default value to 'arr'

If user forget to give value to "largestOfFour" while calling , it will through an error
"TypeError: Cannot read properties of undefined (reading 'length') "

Where undefined means "arr" since user forgot to give value so
arr = undefined

How to overcome with this ?

- By given default value to "arr"

Method 1 :

arr ||= []

Method 2 :

function largestOfFour(arr = [] ) {

//Your code

}

Answer 2

It's working without errors for me.. Do you changed anything?
You are not printing returned value so it don't show any output..
Save code and share link..