Benchmark: Map.has and Map.set

HTML Preparation code:

<!--your preparation HTML code goes here-->

Script Preparation code:

const map = new Map();
Array.from({ length: 100000 }, (_, i) => i).forEach(i => map.set(i, {test: `test${i}`}))

Tests:

Map.has
map.has(8452)
Map.set
map.set(8452, {test: 'test8452'})

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Map.has
Map.set

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 5 months ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:147.0) Gecko/20100101 Firefox/147.0

Browser/OS: Firefox 147 on Mac OS X 10.15

View result in a separate tab

Map.has

1601.0M/s

Map.set

57.4M/s

View exact numbers

Test name	Executions per second
✓ Map.has	1,600,960,512 Ops/sec
Map.set	57,401,564 Ops/sec

Autogenerated LLM Summary (model gpt-4o-mini, generated one year ago):

LLMs can make mistakes. Check important info.

The benchmark outlined in the provided JSON compares the performance of two methods of the JavaScript `Map` object: `Map.has()` and `Map.set()`. Below is an explanation of each method, their pros and cons, and considerations regarding their use.

### Benchmark Overview

1. **Map.has(8452)**:
   - **What is tested**: This test evaluates the performance of the `Map.has()` method, which checks whether a specified key exists in the `Map` object. In this case, the key tested is `8452`.
   - **Performance Metrics**: The benchmark shows that this method can execute around **231,922,784 times per second** on the specified environment.

2. **Map.set(8452, {test: 'test8452'})**:
   - **What is tested**: This test assesses the performance of the `Map.set()` method, which sets a value for the specified key in the `Map` object. Here, the key is `8452`, and it is being set to an object containing a test string.
   - **Performance Metrics**: The benchmark indicates that this method executes approximately **96,817,776 times per second** in the same environment.

### Pros and Cons

#### Map.has
- **Pros**:
  - Fast performance for checking keys, optimized for direct key lookups.
  - Returns a boolean, making it intuitive for usage in conditional statements.
- **Cons**:
  - Only checks for existence; does not alter the `Map` or provide any additional information about the key or value.

#### Map.set
- **Pros**:
  - Both sets and updates values associated with keys, providing flexibility in managing data within the `Map`.
  - Useful for adding new entries or updating existing ones efficiently.
- **Cons**:
  - Generally slower than `Map.has()` because it involves not only checking for key existence but also inserting/updating values.

### Considerations

- **Data Structure**: Both methods belong to the `Map` object, which was introduced in ECMAScript 2015 (ES6) as a way to store key-value pairs, maintaining the insertion order of the keys. This differs from plain JavaScript objects where keys are strings and can lead to prototype chain issues.
- **Use Cases**: If you need to simply verify the existence of a key, use `Map.has()`. If you're modifying the `Map` by adding a new key or updating an existing key's value, use `Map.set()`. The choice between the two directly impacts performance depending on the context.

### Alternatives

1. **Using Plain Objects**: Instead of using `Map`, plain JavaScript objects could also be used for similar key-value pair storage. However, while objects have their advantages (such as simpler syntax), they lack the functionality of `Map`, especially regarding non-string keys, order preservation, and built-in methods for aknowledging the size or existence of keys.

2. **WeakMap and Set**: If memory management is a concern and you want to hold objects as keys, consider `WeakMap`. It allows for garbage collection of keys when there are no other references to them, which is not the case with `Map`.

In summary, the benchmark provides insights into the performance differences between checking for key existence with `Map.has()` and adding or updating entries using `Map.set()`. Understanding the trade-offs of each method helps in choosing the appropriate approach based on the specific requirements of a given task.

Map.has and Map.set (version: 1)

Comparing performance of: `Map.has vs Map.set`

Created: one year ago by: Guest

Go to the latest result

Map.has

Map.set

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model gpt-4o-mini, generated one year ago):

Map.has and Map.set (version: 1)

Comparing performance of: Map.has vs Map.set

Created: one year ago by: Guest

Go to the latest result

Map.has

Map.set

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model gpt-4o-mini, generated one year ago):

Related benchmarks

Comparing performance of: `Map.has vs Map.set`