Laravel create a JSON array
Stefan Bogdanescu
Founder & Senior Architect · 2026-06-29
# Laravel: Mastering the Art of Creating JSON Arrays for Charting Libraries
Trying to create a JSON array for a visualization library like Morris.js often trips up developers. You have all your necessary data points in PHP, but transforming that raw data into the specific nested structure required by JavaScript charting tools can feel like navigating a maze. If you are aiming for an array of objects—where each object represents a single data point (like `{label: 'rent', value: 435}`), rather than parallel arrays—the approach needs to be fundamentally adjusted.
As senior developers, we know that the structure of the output dictates its usability. Getting the JSON format wrong, even by a single bracket or colon, makes debugging JavaScript integration unnecessarily frustrating. This post will walk you through exactly how to restructure your data in Laravel/PHP to achieve the desired array-of-objects format perfectly.
## Understanding the Formatting Discrepancy
Let's first look at why your current attempt resulted in an incorrect structure. You were attempting to build parallel arrays:
```php
// Your original approach result (Incorrect Structure)
$data2 = [
'label' => ['rent', 'heating', ...],
'value' => [435, 30, ...]
];
json_encode($data2); // Produces {"label":[...],"value":[...]}
```
This structure is valid JSON, but it’s not the format that Morris.js or most modern charting libraries expect for a simple data series. These libraries generally require an array where each item is an object containing the key-value pair for that specific point:
```json
[
{"label": "rent", "value": "435"},
{"label": "heating", "value": "30"}
]
```
To achieve this, we need to iterate through our data and construct a *new* array where each element is an associative array containing the `label` and `value`.
## The Correct Approach: Building an Array of Objects
The most efficient way to solve this is to initialize an empty array and populate it inside your loop with complete objects. This ensures that when you use `json_encode()`, PHP serializes the structure exactly as required by the frontend.
Here is the corrected implementation based on your controller logic:
```php
use Illuminate\Support\Facades\Auth;
use App\Models\User; // Assuming your model path
// ... inside your controller method
$user = User::find(Auth::id());
$budget = $user->budget(); // Assuming budget is a relationship or accessor
$labels = ['rent', 'heating', 'utilities', 'internet_tv', 'phone', 'food', 'sweets', 'alcohol_cigs', 'insurance', 'loans', 'finance_other', 'cosmetics', 'medicine', 'clothes_shoes', 'accessories', 'electronics', 'school', 'entertainment', 'food_out', 'holidays', 'books', 'pets', 'gifts', 'car', 'other'];
$chartData = []; // Initialize the final array of objects
foreach ($labels as $label) {
// Calculate the sum for the current label
$cost = $budget->sum($label);
// Create the required object structure and add it to the array
$chartData[] = [
'label' => $label,
// It is often best practice to cast numerical values to strings when preparing for JSON,
// especially if your frontend expects string types.
'value' => (string) $cost
];
}
// Now encode the perfectly structured array
$jsonOutput = json_encode($chartData);
return response()->json($jsonOutput);
```
### Why This Works Better
By initializing `$chartData = []` and using `$chartData[] = [...]` inside the loop, we are building a single, flat array where every element is an independent object.