Benchmark: Map.set() vs Object assignment in loops

Tests:

for-loop + Map.set
const obj = {} const map = new Map() const n = 1000000; for (let i = 0; i < n; i++) { map.set(i, i); }
for-loop + Object assignment
const obj = {} const map = new Map() const n = 1000000; for (let i = 0; i < n; i++) { obj[i] = i; }
forEach + Map.set
const obj = {} const map = new Map() const n = Array(1000000).fill(0) n.forEach((value, index) => { map.set(index, index); })
forEach + Object assignment
const obj = {} const map = new Map() const n = Array(1000000).fill(0) n.forEach((value, index) => { obj[index] = index; })

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
for-loop + Map.set
for-loop + Object assignment
forEach + Map.set
forEach + Object assignment

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 2 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/97.0.4692.71 Safari/537.36

Browser/OS: Chrome 97 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
for-loop + Map.set	9.4 Ops/sec
for-loop + Object assignment	43.4 Ops/sec
forEach + Map.set	5.4 Ops/sec
forEach + Object assignment	22.1 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the benchmark and explain what's being tested, compared options, pros and cons of each approach, and other considerations.

**Benchmark Description**

The benchmark compares three approaches to assigning values to an object or a Map in JavaScript:

1. **For-loop + Object assignment**: Using a traditional for loop to iterate over a range of numbers and assign each value to the object using the dot notation (e.g., `obj[i] = i;`).
2. **For-loop + Map.set**: Using a for loop to iterate over a range of numbers and add entries to a Map using the `set()` method (e.g., `map.set(i, i);`).
3. **ForEach + Object assignment**: Using the Array.prototype.forEach() method to iterate over an array and assign each value to the object using the dot notation.
4. **ForEach + Map.set**: Using the Array.prototype.forEach() method to iterate over an array and add entries to a Map using the `set()` method.

**Libraries and Features Used**

In this benchmark, only built-in JavaScript libraries and features are used. There are no external libraries or frameworks involved.

**Approach Comparison**

Here's a brief summary of each approach:

* **For-loop + Object assignment**: This approach uses traditional iteration and assignment using the dot notation. It's a straightforward and widely supported method.
	+ Pros: Easy to understand, well-supported by most browsers.
	+ Cons: May be slower due to the overhead of dynamic property access.
* **For-loop + Map.set**: Using `Map.set()` is an efficient way to add entries to a Map. This approach leverages the optimized implementation of the `set()` method.
	+ Pros: Efficient, fast, and optimized by browsers.
	+ Cons: May require more memory allocation due to the use of a Map.
* **ForEach + Object assignment**: This approach uses the Array.prototype.forEach() method to iterate over an array. It's a concise way to perform iteration.
	+ Pros: Concise, efficient, and well-supported by most browsers.
	+ Cons: May be slower due to the overhead of function invocation and callback execution.
* **ForEach + Map.set**: Using `Map.set()` within a forEach loop is an efficient way to add entries to a Map while iterating over an array. This approach combines the benefits of both methods.
	+ Pros: Efficient, fast, and optimized by browsers.
	+ Cons: May require more memory allocation due to the use of a Map.

**Other Considerations**

When interpreting these results, keep in mind:

* **Execution frequency**: The number of executions per second is used as the benchmark metric. Higher values indicate faster execution.
* **Device platform**: The test was run on a Mac OS X 10.15.7 system with a Chrome 97 browser. This may not be representative of all platforms or browsers.
* **Memory allocation**: The use of a Map for `Map.set()` and array for `forEach` methods might impact memory usage.

**Alternatives**

If you're interested in exploring alternative approaches, consider:

* Using other data structures like Sets or WeakMaps
* Investigating the performance of different iteration methods (e.g., `while`, `for...of`)
* Examining the impact of caching or memoization on the benchmark results

Keep in mind that these alternatives might not be relevant to the specific problem being solved, and may introduce additional complexity.

Related benchmarks:

Map.set() vs Object assignment in loops (version: 0)

Comparing performance of: for-loop + Map.set vs for-loop + Object assignment vs forEach + Map.set vs forEach + Object assignment

Created: 2 years ago by: Guest

Jump to the latest result

for-loop + Map.set

for-loop + Object assignment

forEach + Map.set

forEach + Object assignment

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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