How can I loop through an array of JSON objects?

Question

I have JSON data that I need to loop through. The data is in a file titled "people.json" that is structured as listed below:

[{"firstname":"John","lastname":"Smith","age":"40"},{"firstname":"Bill","lastname":"Jones","age":"40"}, ...]

I want to read each object in this file and save it (I'm using Mongoose). Here is what I have so far:

var fs = require('fs');
var Person = require('../models/people');

fs.readFile('./people.json', 'utf8', function (err,data) {
    var i;
    for(i = 0; i < data.length; i++) {
        var newPerson = new Person();
        newPerson.firstname = data[i].firstname;
        newPerson.lastname = data[i].lastname;
        newPerson.age = data[i].age;
        newPerson.save(function (err) {});
    }
});

I'm unable to get this to work though. What am I doing wrong?

The loop looks fine. Have you verified that there is no error and that you are actually getting data in your callback? — Brian Driscoll
– Brian Driscoll, Commented Apr 16, 2014 at 18:52
You might want to check out mongoimport, which would be a better way to do this. — Anand Jayabalan
– Anand Jayabalan, Commented Apr 16, 2014 at 18:53

Ibrahim · Accepted Answer · 2016-05-23 13:17:27Z

33

fs.readFile('./people.json', 'utf8', function (err,data) {
  data = JSON.parse(data); // you missed that...
  for(var i = 0; i < data.length; i++) {
    var newPerson = new Person();
    newPerson.firstname = data[i].firstname;
    newPerson.lastname = data[i].lastname;
    newPerson.age = data[i].age;
    newPerson.save(function (err) {});
  }
});

edited May 23, 2016 at 13:17

answered Apr 16, 2014 at 18:52

Ibrahim

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hedzr · Accepted Answer · 2016-05-24 08:45:17Z

12

ES6 for..of can do that too.

fs.readFile('./people.json', 'utf8', function (err,data) {
  for(var item of data) {
     console.log('item: ', [item.firstname, ...]);
  }
});

answered May 24, 2016 at 8:45

hedzr

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Comments

Hossein Safari · Accepted Answer · 2022-12-21 09:02:42Z

0

const parsedData = JSON.parse(JSON.stringify(data));

answered Dec 21, 2022 at 9:02

Hossein Safari

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