Benchmark: Rest Object vs delete

Script Preparation code:

var obj = {
  a:1,
  b:2,
  c:3,
  d:4,
  e:5
}

Tests:

Rest
const { a, b, ...rest } = obj;
Delete
delete obj.a; delete obj.b;

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Rest
Delete

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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Let's dive into the world of JavaScript microbenchmarks.

**What is being tested?**

The provided JSON represents a benchmarking test between two approaches: using the `delete` keyword and spreading an object to remove unused key-value pairs.

The script preparation code creates an object with five properties (keys): `a`, `b`, `c`, `d`, and `e`. The goal is to measure which approach performs better in terms of performance.

**Options compared**

There are two options being compared:

1. **Using the `delete` keyword**: This involves deleting each key individually, like `delete obj.a; delete obj.b;`.
2. **Spreading an object**: This involves using destructuring assignment to remove unused key-value pairs, like `{ a, b, ...obj }`.

**Pros and Cons**

Here's a brief analysis of the two approaches:

1. **Using the `delete` keyword:**
	* Pros:
		+ Easy to understand and implement.
		+ Can be more efficient for smaller objects.
	* Cons:
		+ Inefficient for larger objects, as it requires multiple deletions.
		+ May not work well with nested objects or arrays.
2. **Spreading an object:**
	* Pros:
		+ More efficient for larger objects, as it only requires one operation.
		+ Works well with nested objects and arrays.
	* Cons:
		+ Requires understanding of destructuring assignment syntax.

**Library usage**

There is no explicit library mentioned in the benchmark definition or test cases. However, the use of JavaScript features like destructuring assignment (`{ a, b, ...obj }`) suggests that the code is targeting modern browsers or environments that support this syntax.

**Special JS feature or syntax**

The benchmark uses the `const` keyword to declare variables and the destructuring assignment syntax (`{ a, b, ...rest } = obj;`). These are modern JavaScript features introduced in ECMAScript 2015 (ES6). The use of `const` ensures that the variables are not reassigned, which can help prevent common errors.

**Other alternatives**

If you wanted to rewrite the benchmark using an alternative approach, here are a few options:

1. **Using `Object.keys()` and `forEach()`**: You could iterate over the object's keys and delete each one individually: `Object.keys(obj).forEach(key => delete obj[key]);`.
2. **Using `for...in` loop**: Similar to the previous option, you could use a `for...in` loop to iterate over the object's properties and delete them.

However, these approaches would likely be slower than the original two options being compared in the benchmark.

Related benchmarks:

Rest Object vs delete (version: 0)

Performance benchmark between using the "delete" keyword and spreading the object, removing unused key value pairs.

Comparing performance of: Rest vs Delete

Created: 4 years ago by: Guest

Jump to the latest result

Rest

Delete

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):