Benchmark: Map looping - MeasureThat.net

Script Preparation code:

var map = new Map()
for (let i = 0; i < 10000; i ++) {
  map.set(i, { text: 'a' + i })
}

Tests:

forEach
map.forEach(v => { v.text += 'f' })
for of
for (let v of map) { v.text += 'o' }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
forEach
for of

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):

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks and explore what's being tested on this specific benchmark.

**Benchmark Overview**

The benchmark measures performance differences between two looping constructs: `forEach` and `for...of`. The script preparation code creates a Map object with 10,000 entries, each containing an object with a `text` property. The HTML preparation code is empty, indicating that the test only focuses on JavaScript execution speed.

**Options Compared**

Two options are being compared:

1. **`forEach`**: A method of traversing an iterable (in this case, the Map) and executing a callback function for each item.
2. **`for...of`**: A loop construct that allows iterating over an iterable using a `for...of` statement.

**Pros and Cons**

*   **`forEach`**:
    *   Pros:
        *   Convenient and expressive syntax.
        *   Can be easily chained with other methods (e.g., `map()`).
    *   Cons:
        *   May incur additional overhead due to method invocation and loop control.
        *   Some older browsers might not support it or have limited support.
*   **`for...of`**:
    *   Pros:
        *   Fast and lightweight, with minimal overhead.
        *   Widely supported across modern browsers.
    *   Cons:
        *   More verbose syntax compared to `forEach`.
        *   Requires more manual control over loop variables.

**Library Usage**

There is no explicit library mentioned in the benchmark definition or test cases. However, some libraries might be implicitly used due to dependencies required for browser environment setup (e.g., DOM manipulation).

**Special JS Feature/Syntax**

No special JavaScript features or syntax are explicitly mentioned or tested in this benchmark. The tests focus solely on the looping constructs.

**Alternatives**

If you want to explore alternative looping constructs, here are a few options:

*   **`while` loop**: A traditional loop construct that can be used with manual index management.
*   **Array.prototype.forEach.call()**: An older method for iterating over arrays, which might not offer the same performance as `forEach`.
*   **Manual iteration using `for` loops and indices**: This approach provides fine-grained control but requires more effort to set up.

Keep in mind that these alternatives may have different trade-offs in terms of readability, maintainability, and performance compared to `forEach` and `for...of`.

In conclusion, the Map looping benchmark primarily explores the performance differences between two looping constructs: `forEach` and `for...of`. By comparing these options, developers can gain insights into which approach is faster and more suitable for their specific use cases.

Related benchmarks:

Map looping (version: 0)

Comparing performance of: forEach vs for of

Created: 3 years ago by: Guest

Jump to the latest result

forEach

for of

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):