Retrieve index of an Object in javascript

Question

I've a javascript object inside a variable data like:

data: Object {
   aliquota: 23,
   imponibileLordo: 300,
   imponibileScontato: "",
   imposta: 69
}

In another function i've to iterate the object using an index like:

for ( var index = 0; index < data.length; index++ ) {
    var valueOfIndex = data[index];
    console.log(valueOfIndex);
}

But I get error cause data[0], data[1], data[2], data[3] are not defined.

How can solve this? Important: i've to use a numeric INDEX for cycle for cause I do other operation based on index value.

UPDATE: Ok my goal is another. So i'll upload the script i'm using with the fix I DON'T LIKE but works. (See //ACTUAL FIX comment) Also the fiddle here: https://jsfiddle.net/am3ovL3b/5/

var array_iva = [];

var data = { "impo": 10, "aliq": 20, "other": 30 };
var column = { "title": "TEST 1", "data": data };
array_iva.push(column);

var data = { "impo": 40, "aliq": 50, "other": 60 };
var column = { "title": "TEST 2", "data": data };
array_iva.push(column);

var json_righe = [[ "Imponibile lordo" ], [ "Aliquota %" ], [ "Others" ] ];

for ( var i = 0; i < array_iva.length; i++ ) {

var titolo_colonna_iva = {};

titolo_colonna_iva['title'] = array_iva[i]['title'];

for ( j = 0; j < json_righe.length; j++ ) { //  for each 

    var riga = json_righe[j];

    for ( var k = 0; k < array_iva.length; k++ ) {  //  EMPTY DEFAULT
        riga.push("");
    }

    //  ACTUAL FIX

    if ( j == 0 ) {
        riga[(i+1)] = array_iva[i]['data']['impo'];
    } else if ( j == 1 ) {
        riga[(i+1)] = array_iva[i]['data']['aliq'];
    } else if ( j == 2 ) {
        riga[(i+1)] = array_iva[i]['data']['other'];
    }

      //END ACTUAL FIX

    /*
    THIS DOESn?T WORK
    riga[(i+1)] = array_iva[i]['data'][j];
    */

    json_righe[j] = riga;

}

}

The properties are not numeric! e.g. `aliquota` is `aliquota` not `0`! — Quentin, Jan 29 '18 at 10:06
Objects don't have numeric indexes unless you define them, and even then there's no guarantee they'll be sequential/have no gaps. — Joe Clay, Jan 29 '18 at 10:06
i've update my code with real problem and the fix I use at the moment.... — Giuseppe Lodi Rizzini, Jan 29 '18 at 10:37

score 2 · Answer 1 · answered Jan 29 '18 at 10:06

2

You can use Object.keys to get an array of all keys and loop trough this array to console.log value correponding to each key:

var data = {
   aliquota: 23,
   imponibileLordo: 300,
   imponibileScontato: "",
   imposta: 69
};

Object.keys(data).forEach(key => console.log(data[key]));

answered Jan 29 '18 at 10:06

Faly

13,291
2
19
37

This is ok but doesn't work for my purpose. i've update my code – Giuseppe Lodi Rizzini Jan 29 '18 at 10:36

score 0 · Answer 2 · answered Jan 29 '18 at 10:07

0

To iterate an object use for ..in

var data = {
  aliquota: 23,
  imponibileLordo: 300,
  imponibileScontato: "",
  imposta: 69
}

for (var index in data) {
  var valueOfIndex = data[index];
  console.log(valueOfIndex);
}

answered Jan 29 '18 at 10:07

brk

48,835
10
56
78

score 0 · Answer 3 · answered Jan 29 '18 at 10:07

i've to use a numeric INDEX for cycle for cause I do other operation based on index value.

Then you'll want to reorganize your logic and code to use an array instead of an object, or at least to have your own array of property names in a defined order and loop through that. Although object properties have an order as of ES2015, it's not an order you should use as it depends on how the object was created and what the names of the properties are (e.g., do they look like array indexes or not).

You can loop through the object's properties in the ES2015+ order by using Object.getOwnPropertyNames on the object and looping through the strings in the returned array, e.g.:

Object.getOwnPropertyNames(data).forEach((name, index) => {
    // `name` will be the property name,
    // `index` will be its index in the property order
    // ...
});

...but again, it's not a good idea to rely on those being in any particular order.

Retrieve index of an Object in javascript

3 Answers3