无法读取未定义错误 JavaScript 的属性“forEach”

Question

this is my javascript code but whenever I try to run it, it throws 'Error: TypeError: Cannot read property 'forEach' of undefined' Can anyone please tell me why this is happening and also give me a solution how to fix it?

app.post('/getElements', (req, res) => {
    fs.readFile('items.json', function(error, data) {
        if (error) {
            res.status(500).end()
        } else {
            try {
                const accountId = req.body.accountId //the value of it is 'data'
                const items = JSON.parse(data)

                items.accountId.forEach(function(item) {
                    const price = item.price

                    res.json({
                        price: price
                    })
                })
            } catch (err) {
                console.log('Error: ', err)
            }
        }
    })
})

Answer 1

I would recommend to check if the data that comes in has the format you need, then only run your forEach if accountId is type of array. If not, return something like price not available