CODEWITHSUNDEEP
node.js
Addi Khan
Addi Khan

Reputation: 201

How to solve type error when I add new fields to object in nodejs

I created an object. But when I try to set some values in it an error is thrown. See code below:

function CheckStatus(oldJob, newJob) {
  var obj = {};
  if(newJob && newJob.Status) { 
    if (oldJob.Status.total !== newJob.Status.total) {
      obj.Status.total = newJob.Status.total;
    }
    if (oldJob.Status.charge_description && oldJob.Status.charge_description !== newJob.Status.charge_description) {
      obj.Status.charge_description = newJob.Status.charge_description;
    }
  }
}

TypeError: Cannot set property 'total' of undefined

Upvotes: 0

Views: 112

Answers (2)

Mech45
Mech45

Reputation: 339

Your obj variable has nos property status ! you must create his real structure before !

use lodash _.set :

const _ = require('lodash');

function CheckStatus(oldJob, newJob) {
    let obj = {};
    if (newJob && newJob.Status) {
        if (oldJob.Status.total !== newJob.Status.total) {
            _.set(obj, 'Status.total', newJob.Status.total);
        }
        if (oldJob.Status.charge_description && (oldJob.Status.charge_description !== newJob.Status.charge_description)) {
            _.set(obj, 'Status.charge_description', newJob.Status.charge_description);
        }
    }
}

FYI it return a mutated object not a new object ! ;)

Upvotes: 0

Ronan
Ronan

Reputation: 1512

Well your definition of obj is an empty object. So before setting obj.Status.total you need to define obj.Status, either in the original declaration like so:

var obj = { Status: {} }

or later like so:

obj.Status = {}

Upvotes: 2

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