Unable to get length value of an array in Node Red Javascript

I would like to know the length of an array read inside a function in NodeRed using Javascript but it is not displaying/ returning any value. can someone help me here.

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Here is the code inside the function block in Node-Red

let j = 0;
let array1 = { payload: msg.payload };

j = array1.length;

return j;

I do not see any return value for J. any help ?

I was expecting a value of 50 for J to be displayed on Nodered debug console.