Benchmark: Object.entries VS Object.keys [simple]

Script Preparation code:

function makeid() {
  var text = "";
  var possible = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";

  for (var i = 0; i < 5; i++)
    text += possible.charAt(Math.floor(Math.random() * possible.length));

  return text;
}

window.parentObj = {};

for (let i = 0; i < 100; i++) {
	window.parentObj[makeid()] = makeid();
}

Tests:

Object.entries
const obj = window.parentObj; const newObj = {}; for (const [k, v] of Object.entries(obj)) { newObj[k] = v; }
Object.keys
const obj = window.parentObj; const newObj = {}; for (const k of Object.keys(obj)) { newObj[k] = obj[k]; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Object.entries
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 benchmark and explain what is being tested.

**Benchmark Definition**

The benchmark is designed to compare the performance of two JavaScript methods: `Object.entries` and `Object.keys`. The goal is to determine which method is faster when iterating over an object and creating a new object with the same properties.

**Options Compared**

Two options are compared:

1. **Object.entries**: This method returns an array of a given object's own enumerable property [key, value] pairs.
2. **Object.keys**: This method returns an array of a given object's own enumerable property names.

**Pros and Cons of Each Approach**

Here are the pros and cons of each approach:

*   **Object.entries**:
    *   Pros: More efficient when you need to iterate over both key-value pairs, as it avoids creating multiple intermediate arrays.
    *   Cons: May be slower when only needing the keys, due to the creation of an additional array.
*   **Object.keys**:
    *   Pros: Faster when only needing the keys, as it creates a single array with just the property names.
    *   Cons: Requires two passes through the object (once for getting the keys and another for iterating over them), which can be slower than `Object.entries` in some cases.

**Library Used**

There is no explicit library mentioned in the benchmark definition. However, it's worth noting that both `Object.entries` and `Object.keys` are part of the JavaScript standard library, so any JavaScript engine or environment should support them natively without requiring an external library.

**Special JS Feature/Syntax**

The test uses special JavaScript syntax to create a random string for use as object keys. This is not particularly relevant to the comparison at hand but demonstrates how JavaScript's dynamic nature can be utilized in benchmarking scenarios.

Now that we've covered what's being tested and compared, let's explore other alternatives that could be used to compare these methods:

**Alternative Benchmarking Approaches**

Some alternative approaches for comparing `Object.entries` and `Object.keys` might include:

*   **Using a third-party library**: Libraries like Benchmark.js or micro-benchmark can provide more advanced features and flexibility in benchmarking.
*   **Implementing custom iteration logic**: Depending on the specific requirements, you could create custom functions to iterate over objects and compare their performance.

Ultimately, the choice of approach depends on your specific use case, performance requirements, and desired level of complexity.

Related benchmarks:

Object.entries VS Object.keys [simple] (version: 0)

Comparing performance of: Object.entries vs Object.keys

Created: 3 years ago by: Guest

Jump to the latest result

Object.entries

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):