Benchmark: Iterate Map vs Array

Script Preparation code:

var arr = new Array(100000).fill(1).map((_, i) => i);
var map = new Map(new Array(100000).fill(1).map((_, i) => [`key_${i}`, i]));

Tests:

Iterate Array
var val = 0; for (var i of arr) val += i;
Iterate Map.values()
var val = 0; for (var i of map.values()) val += i;
Iterate Map
var val = 0; for (var [_, i] of map) val += i;

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Iterate Array
Iterate Map.values()
Iterate Map

Fastest: N/A

Slowest: N/A

Latest run results:

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

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I'll break down the benchmark and its results in detail.

**Benchmark Definition:**

The provided JSON defines two benchmarks, both measuring the performance of iterating over an array or map to sum up values.

1. **Iterate Array**: This benchmark tests the performance of iterating over an array using a `for...of` loop with `var i of arr`.
2. **Iterate Map**: This benchmark tests the performance of iterating over a map using:
	* `map.values()`: Returns an iterator over the map's values.
	* `map`: Direct iteration, iterating over the key-value pairs.

**Options Compared:**

The benchmarks compare three approaches:

1. Iterating over an array using `for...of` loop (`Iterate Array`).
2. Iterating over a map's values using `map.values()` iterator (`Iterate Map.values()`).
3. Direct iteration over a map's key-value pairs (`Iterate Map`).

**Pros and Cons:**

1. **Iterate Array**:
	* Pros: Generally faster, since arrays are more optimized for iteration.
	* Cons: Requires array creation with `Array(100000).fill(1).map((_, i) => i)` and the loop index `i` can lead to unnecessary computations.
2. **Iterate Map.values()**:
	* Pros: More efficient than direct iteration, as it avoids iterating over the map's keys and returns only values, reducing memory access overhead.
	* Cons: May incur a slight performance penalty due to the iterator creation and management.
3. **Iterate Map**:
	* Pros: Can be more convenient for some use cases, especially when you need to iterate over both key-value pairs and values separately.
	* Cons: Requires manual iteration over the map's keys, which can lead to additional memory accesses and computations.

**Library/Legacy Code**

There is no specific library mentioned in the benchmark definition or test cases. However, it's worth noting that `for...of` loops with array or map iterators are built-in language features in JavaScript and do not require any external libraries.

**Special JS Feature/Syntax**

There are no special JavaScript features or syntax used in these benchmarks. They use standard JavaScript language features like `for...of` loops, array creation, and object iteration.

**Other Alternatives**

For measuring performance, you may also consider using:

* Benchmarking frameworks like Benchmark.js or benchmark-chrome
* Built-in browser performance tools like Chrome DevTools' Performance tab or Firefox Developer Edition's Performance tab

These alternatives can provide more comprehensive insights into your application's performance and offer additional features for comparing different scenarios.

Related benchmarks:

Iterate Map vs Array (version: 0)

Comparing performance of: Iterate Array vs Iterate Map.values() vs Iterate Map

Created: 3 years ago by: Guest

Jump to the latest result

Iterate Array

Iterate Map.values()

Iterate Map

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):