Convert NodeJs MySQL result to accessible JSON Object

Question

I want to get some data from my database. Example:

  getCarIds: function (callback) {
    db.query("SELECT Id FROM Cars;",
      function (err, result) {
        if (err) throw err;

        result = JSON.stringify(result);

        var cars = [];

        for (var i = 0; i < result.length; i++) {
          var currentCar = result[i];
          var carId = currentCar.id;
          cars.push(carId);
        }

        callback(cars);
      });
  }

I want to store all the ids into an array. Like

cars = [1,2,3,4,5];

The result returns this

[ RowDataPacket { Id: '1' },
  RowDataPacket { Id: '2' },
  RowDataPacket { Id: '3' } ]

So I try to convert it by writing

result = JSON.stringify(result);

this returns me

[{"Id":"1"},{"Id":"2"},{"Id":"3"}]

when I want to access this object by writing

result[0]

I get

[

so obviously

result[0].id

will return

undefined

How can I get all the ids from the object?

you have to parse it, result = JSON.parse(JSON.stringify(result)); — Rahul Sharma
– Rahul Sharma, Commented Feb 14, 2018 at 8:38

Zack · Accepted Answer · 2020-01-27 03:20:50Z

17

Say you have a result array of RowDataPacket from mysql called results. You can use Object.assign(). For example, if you wanted to convert the first element to a regular object:

var normalObj = Object.assign({}, results[0]);

or if you wanted the entire array converted to normal objects:

var normalResults = results.map((mysqlObj, index) => {
    return Object.assign({}, mysqlObj);
});

or more compact syntax:

results = results.map(v => Object.assign({}, v));

edited Jan 27, 2020 at 3:20

answered Jan 27, 2020 at 3:15

Zack

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Comments

Dathan · Accepted Answer · 2018-02-14 08:48:49Z

0

You don't need to stringify the result. Just Process the result as it is.

and use currentCar.Id instead of currentCar.id.

answered Feb 14, 2018 at 8:48

Dathan

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1 Comment

user2402616 Over a year ago

What exactly do you mean by "just Process the result"?

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