Benchmark: map vs object.keys

Script Preparation code:

var obj = {
  'a': {id: 1},
  'b': {id: 1},
  'c': {id: 1},
  'd': {id: 1},
  'e': {id: 1},
  'f': {id: 1},
  'g': {id: 1}
};

var arr = [
  {id: 1},
  {id: 1},
  {id: 1},
  {id: 1},
  {id: 1},
  {id: 1},
  {id: 1}
];

Tests:

map
for (var i=10000; i > 0; i--) { const ids = arr.map(item => item.id) }
Object.keys
for (var i=10000; i > 0; i--) { const ids = Object.keys(obj); }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
map
Object.keys

Fastest: N/A

Slowest: N/A

Latest run results:

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmarking scenario.

**Benchmark Definition**

The benchmark measures the performance of two approaches: using `Array.prototype.map()` and using `Object.keys()`. Both methods aim to extract an array of IDs from two different objects (`obj` and `arr`). However, they differ in their syntax and implementation:

1. **`map()`**: This method creates a new array by executing a provided function on each element of the original array. It iterates over the array elements, applying the function to each one, and returns a new array with the results.
2. **`Object.keys()`**: This method returns an array of strings representing the property names (or keys) of an object.

**Options Compared**

The two options being compared are:

* `map()`: an array-based approach that iterates over an array to extract values.
* `Object.keys()``: an object-based approach that uses a built-in method to get an array of property names.

**Pros and Cons**

* **`map()`**:
	+ Pros:
		- More flexible, as it can be used with any iterable (not just arrays).
		- Can handle more complex transformations.
	+ Cons:
		- Creates a new array, which can lead to increased memory usage.
		- May have overhead due to function invocation and array creation.
* **`Object.keys()`**:
	+ Pros:
		- Less memory-intensive, as it only returns an array of property names (no extra values).
		- Often faster, since it's a built-in method with optimized implementation.
	+ Cons:
		- Limited to objects; won't work with other iterables.

**Library and Purpose**

Neither `map()` nor `Object.keys()` rely on any external libraries. They are both native JavaScript methods or array functions that come with the language itself.

**Special JS Feature or Syntax**

There are no special JS features or syntaxes mentioned in this benchmark. The only potential complexity lies in the fact that `map()` requires an initial element to provide a starting point for iteration (in this case, `arr[0]`). However, this is a standard JavaScript concept and not considered a "special" feature.

**Other Alternatives**

For this specific use case, there are a few alternative approaches you might consider:

* Using `forEach()` instead of `map()`: While `map()` creates a new array, `forEach()` executes a callback function on each element without returning any value.
* Using `reduce()` instead of `map()` or `Object.keys()`: `reduce()` applies a binary accumulator function to an iterable, which can be useful for different types of aggregations.
* Using `for...of` loops: If you need to iterate over the array elements directly, without creating a new array or using built-in methods like `map()` or `forEach()`, a `for...of` loop might be a suitable alternative.

Keep in mind that these alternatives may have different performance characteristics or use cases compared to the original `map()` and `Object.keys()` approaches.

Related benchmarks:

map vs object.keys (version: 0)

Comparing performance of: map vs Object.keys

Created: 5 years ago by: Guest

Jump to the latest result

map

Object.keys

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):