Benchmark: Map get VS Map has get 20122

Script Preparation code:

var i = 0, count = 1000, a;
var map = new Map();

for (i = 0; i < count; i++) {
  if (Math.random() > 0.99) {
    map.set(i, i * i);
  }
}

Tests:

Map 1
for (i = 0; i < count; i++) { a = map.get(i); }
Map 2
for (i = 0; i < count; i++) { if (map.has(i)) { a = map.get(i); } }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Map 1
Map 2

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model gpt-4o-mini, generated 2 days ago):

LLMs can make mistakes. Check important info.

This benchmark is focused on comparing two different methods of accessing values stored in a JavaScript `Map` object. It tests the performance of these methods to understand their efficiency in terms of execution speed.

### Benchmark Overview

1. **Test Name**: The benchmark is named "Map get VS Map has get," indicating it is comparing two approaches related to retrieving data from a `Map`.

2. **Script Preparation**: The preparation code creates a `Map` and populates it with up to 1000 entries. The number of entries is determined randomly, which means some keys will not have corresponding values in the map. The `map.set(i, i * i)` line sets the key-value pairs, where each key `i` is associated with `i` squared.

### Individual Test Cases

**Test Case 1: `Map 1`**
- **Benchmark Definition**: 
    ```javascript
    for (i = 0; i < count; i++) {
      a = map.get(i);
    }
    ```
- **Description**: This test case simply attempts to retrieve a value from the `Map` using the `get` method for every integer from 0 to `count - 1`. If the key exists, it returns the corresponding value, but if it doesn't, it returns `undefined`.

**Test Case 2: `Map 2`**
- **Benchmark Definition**: 
    ```javascript
    for (i = 0; i < count; i++) {
      if (map.has(i)) {
        a = map.get(i);
      }
    }
    ```
- **Description**: This test case checks for the existence of each key first with `map.has(i)`. If the key is present in the `Map`, it retrieves the value using `get`. This method potentially avoids unnecessary calls to `get` for keys that do not exist, which could be a performance improvement over the first method.

### Comparison of Approaches

**Pros and Cons**:

- **Map 1 (Direct `get` call)**:
  - **Pros**:
    - Simplicity in code; straightforward retrieval.
  - **Cons**:
    - Performance may decrease when many attempts to access non-existing keys return `undefined`, especially if the map is sparsely populated.
  
- **Map 2 (Using `has` before `get`)**:
  - **Pros**:
    - More efficient in cases where not all keys exist in the map. By checking for existence first, it avoids unnecessary `get` method calls that will yield `undefined`.
  - **Cons**:
    - Slight overhead from an additional method call (`has`) for each iteration, which can add up depending on the key distribution, although this overhead might be offset by the savings from avoiding unnecessary `get` calls.

### Benchmark Results

From the benchmark results:
- **Map 2** (which uses `has` before `get`) showed a higher execution count per second (8771.16) compared to **Map 1** (5338.04). This indicates that the first approach is less efficient than the second when accessing values in the `Map`, particularly in scenarios with many non-existent keys.

### Other Considerations and Alternatives

1. **Alternatives to `Map`**:
   - **Plain Objects**: In cases where key names are known and fixed or when using strings as keys, plain JavaScript objects can be used instead of Maps. However, this could lead to issues with key collision if not handled properly.
   - **WeakMap**: If you are only working with object keys and want to avoid memory leaks (due to automatic garbage collection of unused keys), `WeakMap` might be a good option, but it has different use cases compared to `Map`.

2. **Other Access Methods**:
   - If data retrieval patterns are predictable, consider alternatives like arrays or using caching mechanisms that may suit the specific use case better.

In conclusion, the benchmark demonstrates the performance implications of different access patterns with `Map` objects, providing insights into effective strategies for efficient data retrieval in JavaScript applications.

Latest run results:

Run details: (Test run date: 3 days ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/17.4 Safari/605.1.15

Browser/OS: Safari 17 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
Map 1	5338.0 Ops/sec
Map 2	8771.2 Ops/sec

Related benchmarks:

Map get VS Map has get 20122 (version: 1)

Map get VS Map has get

Comparing performance of: Map 1 vs Map 2

Created: 3 days ago by: Guest

Jump to the latest result

Map 1

Map 2

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model gpt-4o-mini, generated 2 days ago):