Benchmark: Map get VS Map has get Agag

Script Preparation code:

var i = 0, count = 1000, a;
var map = new Map();

for (i = 0; i < count; i++) {
  if (Math.random() > 0.5) {
    map.set(i, i * i);
  }
}

Tests:

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

Latest run results:

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

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/114.0.0.0 Safari/537.36

Browser/OS: Chrome 114 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
Map 1	7210.1 Ops/sec
Map 2	7292.9 Ops/sec

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

LLMs can make mistakes. Check important info.

**Benchmark Overview**

The provided benchmark measures the performance difference between two approaches to retrieving values from a Map data structure in JavaScript: `map.get()` and `map.has()`. The test creates a large Map with 1000 entries, where half of the entries have a key-value pair, and then iterates over the map using both approaches to retrieve the value associated with each key.

**Approaches Compared**

The two approaches compared are:

1. **`map.get(i)`**: This approach directly retrieves the value associated with the key `i` from the Map.
2. **`map.has(i) && map.get(i)`**: This approach first checks if the key `i` exists in the Map using `map.has(i)`, and then retrieves the value using `map.get(i)`. If the key does not exist, this approach will throw a TypeError.

**Pros and Cons**

* **`map.get(i)`**:
	+ Pros: Directly retrieves the value associated with the key, which is faster since it only needs to perform a hash lookup.
	+ Cons: Throws a TypeError if the key does not exist in the Map. This approach assumes that the key exists, which may not always be the case.
* **`map.has(i) && map.get(i)`**:
	+ Pros: Avoids throwing a TypeError by first checking if the key exists before attempting to retrieve its value.
	+ Cons: Requires two operations (hash lookup and subsequent retrieval), which can be slower than `map.get(i)`.

**Library Usage**

There is no explicit library usage in this benchmark. However, JavaScript's built-in Map data structure is used for both approaches.

**Special JS Feature/Syntax**

None of the test cases use special JavaScript features or syntax beyond standard ECMAScript syntax.

**Other Alternatives**

If you need to optimize your code for performance and want to avoid the `TypeError` thrown by `map.get(i)` when the key does not exist, you could consider using other approaches such as:

* Using a separate data structure (e.g., an object or array) to store the keys and their associated values.
* Implementing a custom `has()` method on your Map implementation that returns a boolean indicating whether the key exists, rather than throwing a TypeError.

Keep in mind that these alternatives may have different performance characteristics and trade-offs depending on your specific use case.

Related benchmarks:

Map get VS Map has get Agag (version: 0)

Map get VS Map has get

Comparing performance of: Map 1 vs Map 2

Created: one year 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 llama3.2:3b, generated 2 months ago):