Using toJSON() to access properties of objects

Question

listData.forEach(function (row, index) {
    console.log(row);       --> output JSON format { _id: 5b0bbae16fcc45381a679186, item1: 'item1', item2: 'item2' }
    console.log(row.item1); --> output undefined

    // If using toJSON() then OK
    var json = row.toJSON();
    console.log(json.item1); --> output item1
});

listData: have get Data from MongoDB with mongoose

But I do not understand why so

[If using toJSON() then OK] although row is JSON format

Where does listData come from? I'm asking this because json is not by default an object but a string. In javascript it has to be parsed as a json object. — Jeroen, Jun 07 '18 at 06:39
Looks like the output is not in JSON format, it is a JS object. — Teemu, Jun 07 '18 at 06:39
thanks for care. @Jeroen listData: get from MongoDB with mongoose `DataMaster.find({ table: 1 }).sort('-created').exec()` — Tính Ngô Quang, Jun 07 '18 at 06:45
thanks for care. @Teemu . If it is a JS object, values can get by `row.item1` ? — Tính Ngô Quang, Jun 07 '18 at 06:47
That's (object) what you've written to your example. Don't guess, check the type. — Teemu, Jun 07 '18 at 06:48
Check out this post: https://stackoverflow.com/questions/20734894/difference-between-tojson-and-json-stringify — Jeroen, Jun 07 '18 at 06:49
@Jeroen Not related, the linked article is related to backbone, this is related to node.js. — Teemu, Jun 07 '18 at 06:51
I'm using mongoose, retrieving values from the DB. This is my code `DataMaster.find({ table: 1 }).sort('-created').exec()` — Tính Ngô Quang, Jun 07 '18 at 06:57

Jalay · Accepted Answer · 2018-06-07T07:07:57.377

1

Mongoose queries will return MongooseDocuments and not the plain JavaScript objects.

Try using the lean() method, something like this:

DataMaster.find({ table: 1 }).sort('-created').lean().exec()

edited Jun 07 '18 at 07:07

answered Jun 07 '18 at 07:00

Jalay

66
1
7

I have used lean() method. and It is OK (no need to use toJSON()) access properties of objects. Because Mongoose queries will return MongooseDocuments. Thanks for help – Tính Ngô Quang Jun 07 '18 at 07:18
@TinhNQ glad that helped! happy coding – Jalay Jun 07 '18 at 07:23

Using toJSON() to access properties of objects

1 Answers1