Bot giving error cannot read property of null

[pwpretz]

My code is :

/*
function sell() {
        bot.chat("/ ds qsell")
        bot.on("windowOpen", (window) => {
            bot.inventory.slots.forEach((item) => {
                if (item) {
                    if (item.type === 859) {
                        window.deposit(859, null, 64);
                    }
                    // console.log(item.type)
                }
            })
        })
        bot.closeWindow(bot.inventory)
        // bot.chat("sold")
    }
*/

it keeps giving me the error :

/*
assert.notStrictEqual(window.selectedItem.type, null)
                                                  ^

TypeError: Cannot read properties of null (reading 'type')
    at clickDest (C:\Users\Haasin azeem\Documents\mr_zxtr\node_modules\mineflayer\lib\plugins\inventory.js:268:51)
    at transferOne (C:\Users\Haasin azeem\Documents\mr_zxtr\node_modules\mineflayer\lib\plugins\inventory.js:265:13)
    at process.processTicksAndRejections (node:internal/process/task_queues:95:5)
    at async transfer (C:\Users\Haasin azeem\Documents\mr_zxtr\node_modules\mineflayer\lib\plugins\inventory.js:246:5)
    at async window.deposit (C:\Users\Haasin azeem\Documents\mr_zxtr\node_modules\mineflayer\lib\plugins\inventory.js:343:7)

Node.js v18.15.0
*/

The problem is in the second if statement :

/*
if (item.type === 859) 
*/

when i remove it the error goes away but then window.deposit gives me error