Benchmark: Reduce(spread) vs Map

Script Preparation code:

var a = [];
for (let i = 0; i < 50; i++) {
    a.push(Number(i) / 10)
}
var mapping = x => ({
    id: x
})
var reducing = (acc, x) => {
    return [...acc, {
        id: x
    }]
}

Tests:

Reduce
a.reduce(reducing, [])
Map
a.map(mapping)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Reduce
Map

Fastest: N/A

Slowest: N/A

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Autogenerated LLM Summary (model gemma2:9b, generated one year ago):

LLMs can make mistakes. Check important info.

This benchmark compares two ways to process an array of numbers in JavaScript: using the `reduce()` method and using the `map()` method.

**Options Compared:**

* **`reduce()` with a custom reducer function:** This approach iterates through the array and builds a new array by applying a function (the `reducing` function in this case) to each element, accumulating a result.
* **`map()` with a simple transformation function:** This approach also iterates through the array but creates a new array by applying a function (the `mapping` function here) to each element, directly transforming it into a new value.

**Pros and Cons:**

* **`reduce()`:**  More versatile because it can perform various operations beyond simple transformations, like calculating sums, finding maximum values, or grouping elements. Can be more complex to understand and write for simple tasks.
* **`map()`:** Simpler and more readable when the goal is to create a new array with transformed elements. Less flexible than `reduce()` if you need to perform more complex calculations or manipulations.

**Code Explanation:**

1. **Preparation Code:** 
   -  Creates an array `a` containing 50 numbers, each calculated as `i / 10`.
   - Defines two functions:
     -  `mapping`: Takes a number and returns an object with the `id` property equal to that number. Used for transforming elements in the `map()` approach.
     -  `reducing`: Takes an accumulator (starting array) and a current element, and appends an object with the `id` property set to the current element to the accumulator. Used for the `reduce()` approach.

2. **Test Cases:**
   -  "Reduce": Executes `a.reduce(reducing, [])`, using the `reduce()` method with the defined `reducing` function and an empty array as the initial value.
   -  "Map": Executes `a.map(mapping)`, using the `map()` method with the defined `mapping` function to transform each element in the array.

**Alternatives:**

* **For Loop:** A more explicit way to iterate through the array and process each element, but can be less concise than using built-in methods like `reduce()` or `map()`.
* **Library Functions:** Some libraries, like Lodash, provide optimized implementations of array methods like `map()` and `reduce()`, which might offer performance improvements in certain scenarios.

Let me know if you have any more questions!

Related benchmarks:

Reduce(spread) vs Map (version: 0)

Comparing performance of: Reduce vs Map

Created: 3 years ago by: Registered User

Jump to the latest result

Reduce

Map

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

Autogenerated LLM Summary (model gemma2:9b, generated one year ago):