Transmitting an "array with key-value pairs" through POST method in AngularJS

Question

Transmitting an "array with key-value pairs" through POST method in AngularJS

Currently, I have a filter object that looks like this:

{
  name: 'text',
  value: 'xxx',
  field: 'firstname'
}

This object represents a filter for a specific field and is updated whenever input field values change. I am attempting to store this object in an array using the following method:

$scope.active_filters[filter.field] = filter;

This way, I can easily identify which filter belongs to which field. The filtering process needs to take place on the server side, so I want to send this array to my API.

$http.post(url, $scope.active_filters)

Upon inspecting in Chrome, I see that there is an array with the desired element, but its length is shown as 0:

[status: Object]
length: 0
  status: Object
    field: "status"
    name: "text"
    value: "x"
    __proto__: Object
__proto__: Array[0]

However, when I attempt to send the data, the object is NOT included in the request. If I manually add the object using

$scope.active_filters.push(filter)

, it does get sent to the server, but it has the index of 0 instead of the desired value.

How can I accomplish both goals - having a named index in my array and successfully sending the data to the API?

javascript ajax angularjs

Answer 1

Answer №1

From what I can tell, your code appears to be structured like this:

var assoc_array = [];
assoc_array["foo"] = "bar";
assoc_array["ipsum"] = "lorem";

In JavaScript, there are no associative arrays like in PHP. Instead, JavaScript uses objects, where everything is considered an object, including arrays.

When you set values in the array using brackets, you are actually assigning properties to the object. As a result, the magical .length property does not update because the array remains empty.

If you modify your code to look like this:

var assoc_array = {}; // <-- Use {} instead of []     
assoc_array["foo"] = "bar";
assoc_array["ipsum"] = "lorem";

You will create an object (not an array) without a .length property.

For using an Array properly, consider this example:

var indexed_array = [];
indexed_array[0] = "bar";
indexed_array[1] = "lorem";
indexed_array.length; // 2
indexed_array[100] = "foo";
indexed_array.length; // 101 - Unlike PHP, JavaScript arrays are never sparse
indexed_array[2]; // undefined

Answer 2

From what I can tell, your code appears to be structured like this:

var assoc_array = [];
assoc_array["foo"] = "bar";
assoc_array["ipsum"] = "lorem";

In JavaScript, there are no associative arrays like in PHP. Instead, JavaScript uses objects, where everything is considered an object, including arrays.

When you set values in the array using brackets, you are actually assigning properties to the object. As a result, the magical .length property does not update because the array remains empty.

If you modify your code to look like this:

var assoc_array = {}; // <-- Use {} instead of []     
assoc_array["foo"] = "bar";
assoc_array["ipsum"] = "lorem";

You will create an object (not an array) without a .length property.

For using an Array properly, consider this example:

var indexed_array = [];
indexed_array[0] = "bar";
indexed_array[1] = "lorem";
indexed_array.length; // 2
indexed_array[100] = "foo";
indexed_array.length; // 101 - Unlike PHP, JavaScript arrays are never sparse
indexed_array[2]; // undefined

Transmitting an "array with key-value pairs" through POST method in AngularJS

Answer №1

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