Benchmark: JS Arr Sums Bad For

Script Preparation code:

var arr = new Array(1000000).fill(0)

Tests:

Map
let sum = 0; arr.map(n => sum += n);
For Loop
let sum = 0; for (let i = 0; i < arr.length; i++) { sum += arr[i]; }
For Reach
let sum = 0; arr.forEach(n => sum += n);
For Of
let sum = 0; for (const num of arr) { sum += num; }
Reduce
arr.reduce((acc, n) => acc + n)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Map
For Loop
For Reach
For Of
Reduce

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/119.0.0.0 Safari/537.36

Browser/OS: Chrome 119 on Windows

View result in a separate tab

Test name	Executions per second
Map	87.8 Ops/sec
For Loop	12.2 Ops/sec
For Reach	205.5 Ops/sec
For Of	162.0 Ops/sec
Reduce	154.3 Ops/sec

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

LLMs can make mistakes. Check important info.

Measuring the performance of different JavaScript iteration methods is crucial for optimizing code and ensuring efficient execution.

**Benchmark Purpose:**

The provided benchmark measures the performance of four common JavaScript iteration methods:

1.  `Map`
2.  `For Loop`
3.  `For Reach` (also known as `for...of`)
4.  `Reduce`

Each test case uses a large array (`1000000`) and iterates over its elements to calculate the sum.

**Options Compared:**

The benchmark compares four different iteration methods:

*   **Map**: Uses the `map()` method to create a new array with the results of applying a provided function to each element.
*   **For Loop**: Uses a traditional `for` loop to iterate over the array elements.
*   **For Reach** (also known as `for...of`): Uses the `for...of` loop syntax to iterate over the array elements.
*   **Reduce**: Uses the `reduce()` method to apply a function to each element in the array and reduce it to a single value.

**Pros and Cons of Each Approach:**

Here's a brief summary of the pros and cons of each approach:

*   **Map**: Pros - concise syntax, creates a new array with transformed values. Cons - can be slower due to creating an additional array.
    *   When to use: when you need to perform multiple operations on data and want a clean, declarative code structure.
*   **For Loop**: Pros - no overhead from creating a new array, direct access to elements. Cons - more verbose syntax, can lead to errors if not implemented carefully.
    *   When to use: when speed is critical, and you need fine-grained control over the iteration process.
*   **For Reach (for...of)**: Pros - concise syntax, easy to read and write. Cons - may incur some overhead due to the loop's nature.
    *   When to use: when conciseness and readability are prioritized, and performance is not a critical concern.
*   **Reduce**: Pros - concise syntax, efficient for aggregating data. Cons - can be slower than other methods if the initial value is large or complex.
    *   When to use: when you need to aggregate data in a single operation, such as summing or reducing an array.

**Library and Purpose:**

In the provided benchmark, no external libraries are used besides JavaScript's built-in functions. However, if we consider third-party libraries for optimization purposes, some popular ones include:

*   Lodash: Provides utility functions, including performance-optimized iterations like `lodash.each` and `lodash.reduce`.
*   Underscore.js: Offers a range of utility functions, including performance-enhanced iterations like `_.each` and `_.reduce`.

**Special JavaScript Feature or Syntax:**

The benchmark doesn't explicitly use any special JavaScript features or syntax. However, it's worth mentioning that the `for...of` loop, introduced in ECMAScript 2015, is a modern iteration method that provides a concise and expressive way to iterate over iterable objects.

**Alternatives:**

If you're looking for alternative methods to measure performance, consider:

*   Using a micro-benchmarking library like `micro-benchmark` or ` benchmark.js`, which offer more comprehensive features and customization options.
*   Leveraging browser-specific performance APIs, such as Chrome's `performance.now()` or Firefox's `performance.measure()`.
*   Utilizing parallel processing frameworks like Web Workers or Workers threads to compare performance across multiple cores.

Keep in mind that each approach has its strengths and weaknesses. Choosing the right method depends on your specific use case, performance requirements, and code structure goals.

Related benchmarks:

JS Arr Sums Bad For (version: 1)

JS Memory Tests

Comparing performance of: Map vs For Loop vs For Reach vs For Of vs Reduce

Created: one year ago by: Registered User

Jump to the latest result

Map

For Loop

For Reach

For Of

Reduce

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):