Cannot make post request containing an array in node - node.js

Question

I am a beginner who have been banging my head for days with this problem I got really really stuck with.
Basically I just want to make a post request using node and express. The object will be created dynamically, but this is my hard coded example. myObj contain an array because I want to do one insert to the database for each item later on server side.
let myObj = {
id: 50,
damage_type: ["missing", "broken", "light"]
}
// Parse myObj to JSON string to be sent
let myjsonObj = JSON.stringify(myObj);
console.log(myjsonObj );
// {"poi":50,"damage_type":["missing","broken","light"]}
postDamage(myjsonObj )
function postDamage(damage) {
$.post({
type: 'POST',
url: '/damage',
data: damage
}).
done(function (damage) {
// Do things
}
router.post('/damage', (req, res) =>
{
let data = req.body;
console.log(data)
// This is what I get in the node terminal which is nonsense, I cannot work with
{ '{"id":50,"damage_type":["missing","broken","light"]}': '' }
I expect it to look like {"id":50,"damage_type":["missing","broken","light"]}
So I can loop through the damage_type creating new objects with this structure
createSQLfunction({id:50, damage_type:"missing"})
});
If I dont stringify my myObj the node terminal is printing
{poi:'50', 'damage_type[]: [ 'missing','broken','light']} Where does the extra [] come from?!
What am I doing wrong not to be able to send an array inside an object to the server side?

Answer 1

From the jquery website:
data
Type: PlainObject or String or Array
Data to be sent to the
server. It is converted to a query string, if not already a string.
It's appended to the url for GET-requests. See processData option to
prevent this automatic processing. Object must be Key/Value pairs. If
value is an Array, jQuery serializes multiple values with same key
based on the value of the traditional setting (described below).
The traditional setting appears to be whether it url-encodes as key[]=val1&key[]=val2 or just key=val1&key=val2. You can give it a try, YMMV.
Or you could make your life a lot easier and just serialize the json yourself, instead of messing with jquery's url-encoding.
*Edit: In answer to your question about best practices: Back before JavaScript form submissions became popular, the two standard ways of submitting a form were application/x-www-form-urlencoded or multipart/form-data. The latter was mostly used if you had file(s) you were submitting with a form.
However with the advent of JavaScript XHR (ajax) form submissions, it has become much more common/popular to use JSON instead of either of these formats. So there is absolutely nothing at all wrong with doing something like data: JSON.stringify(object) when you submit your data, and then just instruct your server to read the JSON.
In fact it's probably both easier and faster. And it is a very popular method, so no worries about going against modern best practices.