Benchmark: Testing filter vs foreach

Script Preparation code:

var x = {
  "servicesSummary": [
    {
      "serviceGroup": "Publicacion_Ofertas",
      "availableCredits": 3
    },
    {
      "serviceGroup": "Identidades_Generales",
      "availableCredits": 400
    },
    {
      "serviceGroup": "Identidades_por_Categoria",
      "availableCredits": 0
    },
    {
      "serviceGroup": "Reportes_PDA",
      "availableCredits": 11
    },
    {
      "serviceGroup": "Ofertas_Destacadas",
      "availableCredits": 0
    },
    {
      "serviceGroup": "Ofertas_Premium",
      "availableCredits": 0
    },
    {
      "serviceGroup": "Ofertas_Destacadas_Premium",
      "availableCredits": 0
    },
    {
      "serviceGroup": "Nota_de_Credito",
      "availableCredits": 0
    },
    {
      "serviceGroup": "Descuento",
      "availableCredits": 0
    },
    {
      "serviceGroup": "Servicios_MyOCC",
      "availableCredits": 0
    },
    {
      "serviceGroup": "HELLO_English_Course",
      "availableCredits": 0
    },
    {
      "serviceGroup": "Curriculo_Confidencial",
      "availableCredits": 0
    },
    {
      "serviceGroup": "Result_Placement_Test",
      "availableCredits": 0
    },
    {
      "serviceGroup": "Reporte_PDA_Candidato",
      "availableCredits": 0
    },
    {
      "serviceGroup": "Perfiles_Mercer",
      "availableCredits": 0
    },
    {
      "serviceGroup": "HELLO_Course_Pack",
      "availableCredits": 0
    },
    {
      "serviceGroup": "Publicaciones_Destacadas_Premium",
      "availableCredits": 0
    }
  ]
}

Tests:

Filter
const y = x.servicesSummary.filter((element) => { switch (element.serviceGroup) { case 'Publicacion_Ofertas': return {publish: element.availableCredits}; case 'Ofertas_Destacadas': return {outstanding: element.availableCredits}; case 'Publicaciones_Destacadas_Premium': return {premium: element.availableCredits} default: } });
Foreach
const credits = { outstanding: 0, publish: 0, premium: 0 }; x.servicesSummary.forEach(element => { switch (element.serviceGroup) { case 'Publicacion_Ofertas': credits.publish = element.availableCredits; break; case 'Ofertas_Destacadas': credits.outstanding = element.availableCredits; break; case 'Publicaciones_Destacadas_Premium': credits.premium = element.availableCredits; break; default: break; } });

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Filter
Foreach

Fastest: N/A

Slowest: N/A

Latest run results:

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Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):

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I'll break down what's being tested in this benchmark, comparing the performance of two approaches: `filter()` and `forEach()`, in the context of filtering an array of objects.

**Benchmark Definition**

The benchmark defines a test case with a JSON object `x` containing an array of services summary. The task is to filter this array to extract specific information based on the service group.

**Filter Approach**

The first individual test case uses the `filter()` method:
```javascript
const y = x.servicesSummary.filter((element) => {
  switch (element.serviceGroup) {
    case 'Publicacion_Ofertas':
      return { publish: element.availableCredits };
    case 'Ofertas_Destacadas':
      return { outstanding: element.availableCredits };
    case 'Publicaciones_Destacadas_Premium':
      return { premium: element.availableCredits }
    default:
  }
});
```
This code uses a `switch` statement to determine which properties to extract from each element based on the service group.

**Foreach Approach**

The second individual test case uses the `forEach()` method:
```javascript
x.servicesSummary.forEach(element => {
  switch (element.serviceGroup) {
    case 'Publicacion_Ofertas':
      credits.publish = element.availableCredits;
      break;
    case 'Ofertas_Destacadas':
      credits.outstanding = element.availableCredits;
      break;
    case 'Publicaciones_Destacadas_Premium':
      credits.premium = element.availableCredits;
      break;
    default:
  }
});
```
This code uses a `switch` statement to assign extracted values to an object `credits`.

**Pros and Cons**

Both approaches use a similar pattern, but with different performance implications:

*   **Filter Approach:**
    *   Pros:
        *   More concise and readable
        *   Less chance of side effects due to the pure function nature of `filter()`
    *   Cons:
        *   May incur additional overhead due to the array filter operation
*   **Foreach Approach:**
    *   Pros:
        *   Can be more efficient since it avoids the overhead of array filtering
    *   Cons:
        *   More verbose and error-prone, especially with complex logic

**Other Considerations**

Keep in mind that these approaches are comparing:

1.  Array operations (filtering vs iterating over each element)
2.  Method call performance
3.  Memory allocation for the resulting objects (`y` in the filter case)

It's also worth noting that some browsers or environments might optimize `filter()` or `forEach()` differently.

**Alternative Approaches**

Other alternatives to consider when filtering arrays:

1.  **map()**: Similar to `filter()`, but returns a new array with transformed values.
2.  **reduce()**: Reduces an array to a single value based on a callback function.
3.  **Lodash's _.filter()` or _.pick() functions**: Can provide more concise and readable implementations, especially for complex filtering logic.

In conclusion, the benchmark is testing two common approaches to filter arrays in JavaScript: `filter()` vs `forEach()`. While both have their pros and cons, understanding these differences can help you choose the most efficient approach for your specific use cases.

Related benchmarks:

Testing filter vs foreach (version: 0)

Comparing performance of: Filter vs Foreach

Created: 3 years ago by: Guest

Jump to the latest result

Filter

Foreach

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):