Benchmark: entries vs keys lookup

Script Preparation code:

var obj = {
	something: 9,
  	somethingelse: 10000
}

Tests:

entries
return Object.entries(obj).map(([key, value]) => value)
keys
return Object.keys(obj).map((key) => obj[key])

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
entries
keys

Fastest: N/A

Slowest: N/A

Latest run results:

No previous run results

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

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**Benchmark Definition**
The benchmark measures the performance difference between using `Object.entries` and `Object.keys` to access object values in a JavaScript object.

**Script Preparation Code**
The script creates an object `obj` with two properties: `something` and `somethingelse`, both initialized with large numbers (9 and 10000, respectively). This object is used as the test data for both benchmarks.

**Html Preparation Code**
There is no HTML preparation code provided, which means that only JavaScript performance is being measured.

**Test Cases**

There are two individual test cases:

1. **entries**: The benchmark uses `Object.entries(obj)` to get an array of key-value pairs from the object. It then maps over this array, returning only the values (`value` in the map callback). This approach returns all values from the object, even if some keys are missing or don't exist.
2. **keys**: The benchmark uses `Object.keys(obj)` to get an array of keys from the object. It then maps over this array, returning the value associated with each key (`obj[key]`). This approach only accesses existing keys in the object.

**Library and Features**
Neither of these test cases relies on any external libraries or special JavaScript features. The standard ECMAScript syntax is used throughout.

**Pros and Cons**

* **entries**:
	+ Pros: Returns all values from the object, which might be useful if you need to process every value in a predictable way.
	+ Cons: Can be slower due to the overhead of creating an array and mapping over it. Additionally, this approach can return null or undefined if a key is missing from the object.
* **keys**:
	+ Pros: Only accesses existing keys in the object, which can lead to faster performance. This approach also returns an empty array if the object has no keys.
	+ Cons: Requires iterating over each key in the object, which might be slower for very large objects.

**Other Considerations**

When comparing these two approaches, consider the following:

* If you need to access all values in an object, `entries` might be a better choice. However, if you only need to access existing keys and their associated values, `keys` is likely a better option.
* The performance difference between these two approaches will depend on the size of the object being tested. For very large objects, `keys` might be faster due to the reduced number of operations.

**Alternative Approaches**

If you're looking for alternative ways to access object values in JavaScript, consider:

* Using array destructuring or object spread syntax (`{ ...obj }`) to create a new object with only the desired keys.
* Using `Object.fromEntries()` (available in ECMAScript 2017) to create an object from an array of key-value pairs.

Keep in mind that these alternatives might have different performance characteristics compared to using `Object.keys` and `map`.

Related benchmarks:

entries vs keys lookup (version: 0)

Comparing performance of: entries vs keys

Created: 3 years ago by: Guest

Jump to the latest result

entries

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):