Benchmark: Object.keys vs Object.entries

Script Preparation code:

window.values = {}
for (let i = 0; i < 1000; i++) {
    values[i] = i + 1
}

Tests:

1
Object.entries(window.values).sort((a, b) => { if (a[0] > b[0]) { return -1 } else if (a[0] < b[0]) { return 1 } else { return 0 } })
2
Object.keys(window.values).sort((a, b) => { if (a > b) { return -1 } else if (a < b) { return 1 } else { return 0 } })

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
1
2

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 dive into the world of JavaScript microbenchmarks on MeasureThat.net.

**What is being tested?**

The provided benchmark measures the performance difference between two approaches to iterate over an object: `Object.keys()` and `Object.entries()`. The test case creates a large array-like object (`window.values`) with 1000 properties, each initialized with a value from 1 to 1000.

**Options compared:**

There are two options being compared:

1. **`Object.keys()`**: Returns an array of a given object's own enumerable property names.
2. **`Object.entries()`**: Returns an array of a given object's own enumerable key-value pairs.

**Pros and Cons:**

* `Object.keys()`: Pros:
	+ Generally faster than `Object.entries()` since it only returns the keys, not the values.
	+ May be more cache-friendly, as it doesn't require loading the entire object into memory.
* `Object.entries()`: Pros:
	+ Returns both the key and value pairs, which can be useful for certain use cases (e.g., sorting by key).
	+ Can be faster than `Object.keys()` if the object is small, since it needs to load all values into memory.

Cons:

* `Object.keys()` may have slower performance on very large objects due to the need to iterate over a smaller set of keys.
* `Object.entries()` may consume more memory due to loading the entire object into memory.

**Library and purpose:**

None are explicitly mentioned in the benchmark. However, it's worth noting that both `Object.keys()` and `Object.entries()` rely on the ECMAScript standard for JavaScript objects.

**Special JS feature or syntax:**

There is no specific special JS feature or syntax being tested. The focus is solely on the performance difference between these two object iteration methods.

**Other alternatives:**

For iterating over objects, you can also consider using:

* `for...in` loop, which iterates over both enumerable and non-enumerable properties.
* `Array.prototype.forEach()`, which iterates over an array-like object (including objects) using a callback function.
* Modern JavaScript's `Object.values()` or `Object.keys()` in combination with `forEach()` or `map()` for more complex use cases.

Keep in mind that the choice of iteration method depends on your specific requirements and performance constraints. MeasureThat.net helps you experiment with different approaches to find the most efficient solution for your use case.

Related benchmarks:

Object.keys vs Object.entries (version: 0)

Comparing performance of: 1 vs 2

Created: 4 years ago by: Registered User

Jump to the latest result

1

2

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):