Why am I getting undefined while accessing an array inside an object?

Question

let newdata = await tripModel.find( { tripId: ID }, {salesOrder:1, no: "$deliveryDetails.invoiceNo", _id: 0 } );

let nullInvoices = [];

console.log("vvvvvvv", newdata[0].salesOrder);
for (let i = 0; i < newdata[0].no.length; i++) {
  if (newdata[0].no[i] === null)
    nullInvoices.push({
      SO: newdata[0].salesOrder[i],
      invoice: newdata[0].no[i],
    });
}`

//error: vvvvvvv { salesOrder: [ 623d917d4c9f21730ace6256, 623da8bbeae48b2f34372a95, 623da8bbeae48b2f34372a92, 623d98964c9f21730ace642c ], no: [ null, '0900009293', '0900009294', null ] } reason TypeError: Cannot read properties of undefined (reading 'length')

I need to access "no", but it is throwing as undefined.

I think you need this : newdata[0].salesOrder.no.length

Tushar Shahi
– Tushar Shahi

2022-03-30 07:19:20 +00:00
Commented Mar 30, 2022 at 7:19 — Tushar Shahi
– Tushar Shahi, Commented Mar 30, 2022 at 7:19

Nitheesh · Accepted Answer · 2022-03-30 07:35:41Z

Since your

console.log("vvvvvvv", newdata[0].salesOrder); statement returns

{
    salesOrder: [ 623d917d4c9f21730ace6256, 623da8bbeae48b2f34372a95, 623da8bbeae48b2f34372a92, 623d98964c9f21730ace642c ],
    no: [ null, '0900009293', '0900009294', null ],
}

your iteration must be like as below

let nullInvoices = [];

console.log("vvvvvvv", newdata[0].salesOrder);
for (let i = 0; i < newdata[0].salesOrder.no.length; i++) {
  if (newdata[0].salesOrder.no[i] === null)
    nullInvoices.push({
      SO: newdata[0].salesOrder.salesOrder[i],
      invoice: newdata[0].salesOrder.no[i],
    });
}

Sample Implementation

const newdata = [{}];

newdata[0].salesOrder = {
  salesOrder: ['623d917d4c9f21730ace6256', '623da8bbeae48b2f34372a95', '623da8bbeae48b2f34372a92', '623d98964c9f21730ace642c'],
  no: [null, '0900009293', '0900009294', null],
}

let nullInvoices = [];

for (let i = 0; i < newdata[0].salesOrder.no.length; i++) {
  if (newdata[0].salesOrder.no[i] === null)
    nullInvoices.push({
      SO: newdata[0].salesOrder.salesOrder[i],
      invoice: newdata[0].salesOrder.no[i],
    });
}

console.log(nullInvoices);

A1exandr Belan · Accepted Answer · 2022-03-30 08:32:14Z

1

Actually, you can make an invoices object first, and then filter it by any condition:

const data = {salesOrder: [ '623d917d4c9f21730ace6256', '623da8bbeae48b2f34372a95', '623da8bbeae48b2f34372a92', '623d98964c9f21730ace642c'],no: [ null, '0900009293', '0900009294', null ]};

const invoices = data.salesOrder
  .map((SO, index) => ({ SO, invoice: data.no[index] }));

const nullInvoices = invoices
  .filter(({ invoice }) => invoice === null);
  
console.log(nullInvoices);

.as-console-wrapper{min-height: 100%!important; top: 0}

edited Mar 30, 2022 at 8:32

answered Mar 30, 2022 at 8:26

A1exandr Belan

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