Benchmark: Map get VS Map has

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

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Map get
Map has

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 9 months ago)

User agent: Mozilla/5.0 (X11; Linux x86_64; rv:140.0) Gecko/20100101 Firefox/140.0

Browser/OS: Firefox 140 on Linux

View result in a separate tab

Test name	Executions per second
Map get	118100.6 Ops/sec
Map has	99156.6 Ops/sec

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

LLMs can make mistakes. Check important info.

I'd be happy to help you understand the provided benchmark.

**Benchmark Definition JSON**

The provided JSON defines a JavaScript microbenchmark for comparing the performance of two operations: `map.get()` and `map.has()`. The benchmark is defined by the following properties:

*   **Name**: "Map get VS Map has"
*   **Description**: A brief description of the benchmark, which in this case, only mentions that it compares the two operations.
*   **Script Preparation Code**: A JavaScript code snippet that creates a new `Map` object and populates it with 1000 key-value pairs. The keys are generated randomly using `Math.random() > 0.5`, and the values are calculated as `i * i`. This code ensures that both operations will be executed on non-empty maps.
*   **Html Preparation Code**: An empty string, indicating that no HTML preparation is required for this benchmark.

**Individual Test Cases**

The benchmark consists of two individual test cases:

1.  **Test Case 1: "Map get"**
    *   Benchmark Definition: `for (i = 0; i < count; i++) {\r\n  a = map.get(i);\r\n}`
2.  **Test Case 2: "Map has"**
    *   Benchmark Definition: `for (i = 0; i < count; i++) {\r\n  a = map.has(i);\r\n}`

**Library Used**

Neither of the test cases uses any external libraries, so no library is explicitly mentioned.

**Special JS Features/Syntax**

There are no special JavaScript features or syntax used in this benchmark.

**Pros and Cons of Different Approaches**

When comparing `map.get()` and `map.has()`, consider the following pros and cons:

*   **`map.get()`**:
    *   Pros: Typically faster, since it directly returns the value associated with a given key without iterating through the map's entries.
    *   Cons: If the key is not present in the map, it will return `undefined`. This can lead to edge cases and potential errors if you're using this method for validation or comparison purposes.
*   **`map.has()`**:
    *   Pros: Returns a boolean value (`true` or `false`) indicating whether the specified key exists in the map. This allows for more predictable behavior and avoids edge cases like returning `undefined`.
    *   Cons: May be slightly slower than `map.get()`, as it requires an additional iteration through the map's entries to check if the key is present.

**Other Considerations**

When deciding between `map.get()` and `map.has()`, consider the specific requirements of your use case. If you need to perform a simple lookup without caring about the value associated with the key, `map.has()` might be a better choice. However, if you need to retrieve the value directly or don't care about the existence check, `map.get()` is likely a faster option.

**Alternative Approaches**

If you're looking for alternative ways to optimize your map lookup performance, consider using:

*   **Sparse Maps**: If some keys are guaranteed to be absent in your map, creating a sparse map can reduce memory usage and potentially improve performance.
*   **Iterating through Map Entries Directly**: Instead of relying on `map.has()` or `map.get()`, you can iterate through the map's entries using a `for...of` loop to access both the key and value associated with each entry.

Keep in mind that these alternative approaches might add complexity to your code and may not always lead to performance improvements, depending on your specific use case.

Related benchmarks:

Map get VS Map has (version: 0)

Map get VS Map has get

Comparing performance of: Map get vs Map has

Created: 3 years ago by: Guest

Jump to the latest result

Map get

Map has

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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