Javascript对象到数组，长度= 0

Question

I'm building a webshop where users are able to add products for one of more stores in their basket and checkout (like AliExpress).

On the cart overview page, the content of the basket is shown sorted by store. If the same product is added multiple times over different stores, the product is show by every store.

Now, I want to create an order for every store with the products ordered by that store. I'm using Angular to create the list with products ordered/filtered by store. That data will be sent to my Node.JS server, to loop the contents and create some orders with items.
The problem, I think, is that the data is processed like a 'object' and not an 'array'. I have found a function which converts a object to an array, but the length is still '0'.

How can I process the data so I can loop through the different items?

AngularJS code to sort cart by store

$scope.filterProducts = function(groupName) {
    $scope.productList = [];
    $http({
      method: 'GET',
      xhrFields: {withCredentials: true},
      url: '/loadCart'
    }).then(function successCallback(response){
        if (response.data) {
            var mapByShop = function(arr, groupName) {
                return arr.reduce(function(result, item) {
                    result[item[groupName]] = result[item[groupName]] || {};
                    result[item[groupName]][item['productId']] = item;
                    console.log('GROUPNAME en RESULT', groupName, result);
                    return result;
                }, {});
            };
            if (response.data.length > 0) {
                if (groupName == 'shopName') {
                    $scope.productList = mapByShop(response.data, groupName);
                } else {
                    $scope.checkoutList = mapByShop(response.data, groupName);
                }
            }
        }
    }, function errorCallback(response){
        console.log(response);
    });
  }

The $scope.productList is sent as 'data' in a $http POST function.

Node.JS code to convert an object to an array

function convertObjectToArray(object, cb){
    var cartContent = [];
    for (var i in object) {
        cartContent[i] = object[i];
    }
    console.log("convertObjectToArray");

    return cb(cartContent);
}

Code to process the data (where length is zero)

convertObjectToArray(req.body.cart, function(result){
    console.log(isArray(result));
    console.log('result', result);
    console.log("lenght", result.length);
})

FYI: the isArray function

function isArray(myArray) {
    return myArray.constructor.toString().indexOf("Array") > -1;
}

Answer 1

if array order is not important, you should use

cartContent.push(object[i]);

It will update the .length property automaticly

Answer 2

Your problem is that you are adding properties to the array object, and not using the Array API to insert at integer locations in the object. This means the array essentially remains "empty". If you key on an integer when inserting into the array then your code will work better.

The broken bit:

for (var i in object) {
    cartContent[i] = object[i];
}

i is a string key here and will not increment the length of the Array unless the value coerces to an integer value (I think).

Something like this might work:

// Untested...
var keys = Object.keys(object);
for (var i = 0; i < keys.length; i++) {
    cartContent[i] = object[keys[i]];
}

Or like the other answer suggested, use the push API.

Aside:

If you are in a modern JS engine you can:

1. Use Object.values , or

2. Write a couple of utility functions and convert an object to an array using the following

:

var o = iterable({foo:'fooValue', bar: 'barValue'});
console.log([...o]);

The utility functions:

function iterable(o) {
    if(o[Symbol.iterator]) {
        return o;
    }

    o[Symbol.iterator] = iter.bind(null, o);
    return o;
}

function* iter(o) {
    var keys = Object.keys(o);
    for (var i=0; i<keys.length; i++) {
        yield o[keys[i]];
    }
}