Benchmark: Map has VS Map get

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:

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

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
has
get

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 2 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

Test name	Executions per second
has	258239.8 Ops/sec
get	238299.2 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 explain what's being tested in the provided JSON benchmark.

The benchmark is comparing two approaches:

**Approach 1: `map.has(i)`**

This line checks if a key exists in the Map object using the `has()` method. The pros of this approach are:

* It's concise and easy to read.
* It's likely to be faster than getting the value directly, since it only requires a single lookup.

However, there are some potential cons:

* If you need to get the value associated with that key, using `map.has(i)` will result in another lookup, which could lead to slower performance.
* In this specific benchmark, we're measuring the time it takes to execute the line of code itself, so any additional lookups may not be significant.

**Approach 2: `map.get(i)`**

This line retrieves the value associated with a key using the `get()` method. The pros of this approach are:

* It allows you to retrieve the actual value associated with the key, which might be useful in certain situations.
* In this benchmark, we're measuring the time it takes to execute a single line of code that's supposed to return a value.

However, there are some potential cons:

* Like `map.has(i)`, getting the value directly may lead to slower performance since you need to perform an additional lookup.
* You might be overpaying for the overhead of retrieving a value that's not actually needed if you're just using it once (like in this benchmark).

**Library: None**

The benchmark doesn't use any external libraries.

**Special JavaScript feature: None**

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

Now, let's talk about other alternatives:

* **Using `in` operator**: In some situations, you can use the `in` operator to check if a key exists in an object (including Maps). However, this approach is not commonly used for performance-critical code, and it may have different lookup patterns compared to `has()` or `get()`.
* **Using iterators or destructuring**: If you need more fine-grained control over the iteration process or want to simplify your code, you might consider using iterators or destructuring. However, this would likely involve more complex setup and may not be relevant for simple benchmarks like this one.

Overall, the benchmark is testing two common use cases for Maps in JavaScript: checking if a key exists (using `has()`), and retrieving the value associated with that key (using `get()`). The results will help users understand which approach to take depending on their specific use case.

Related benchmarks:

Map has VS Map get (version: 0)

Map has VS Map get

Comparing performance of: has vs get

Created: 2 years ago by: Guest

Jump to the latest result

has

get

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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