Benchmark: Map vs Object property check

Script Preparation code:

var map = new Map();
var obj = {};
var i = 0, count = 1000, a;
for (i = 0; i < count; i++) {
	map.set('a', 5);
}
                      
for (i = 0; i < count; i++) {
	obj['a'] = 5;
}

Tests:

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

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
obj.hasOwnProperty
map.get
obj.a
map.has

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 8 months ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/137.0.0.0 Safari/537.36

Browser/OS: Chrome 137 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
obj.hasOwnProperty	10069.3 Ops/sec
map.get	10323.3 Ops/sec
obj.a	10590.8 Ops/sec
map.has	10252.5 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the benchmark and its components.

**Benchmark Overview**

The benchmark is designed to compare the performance of three different approaches for checking if a property exists in an object or a Map:

1. `obj.hasOwnProperty('a')`
2. `map.get('a')` (for Maps)
3. `obj.a` (direct property access)

Each test case measures the execution speed of these approaches.

**Options Compared**

The benchmark compares the following options:

* Direct property access (`obj.a`)
* Property access using `hasOwnProperty()` (`obj.hasOwnProperty('a')`)
* Property access using `get()` method (`map.get('a')` for Maps)

These options have different performance characteristics, which we'll discuss below.

**Pros and Cons**

1. **Direct Property Access (`obj.a`)**
	* Pros:
		+ Fastest approach (no function call overhead)
	* Cons:
		+ May throw an error if the property doesn't exist
		+ Not supported for Maps (since they don't have a `hasOwnProperty()` method)
2. **Property Access using `hasOwnProperty()` (`obj.hasOwnProperty('a')`)**
	* Pros:
		+ Safe (throws an error instead of throwing NaN)
	* Cons:
		+ Slower than direct property access due to the function call overhead
3. **Property Access using `get()` method (`map.get('a')` for Maps)**
	* Pros:
		+ Safe (throws an error instead of throwing NaN)
	* Cons:
		+ Only available for Maps, not objects
		+ Slower than direct property access due to the function call overhead

**Library and Special Features**

In this benchmark, no special JavaScript features or libraries are used beyond the standard language.

**Considerations**

When choosing between these approaches, consider the following:

* If you need a safe way to check if a property exists without risking errors, use `hasOwnProperty()` or `get()`.
* If performance is critical and the property is guaranteed to exist, use direct property access (`obj.a`).

Now, let's take a look at some general alternatives to these approaches:

Alternatives to Direct Property Access:

* **Bracket notation**: Instead of using dot notation (e.g., `obj.a`), you can use bracket notation (e.g., `[a]`) for accessing properties.
* **Object.keys()`: You can use the `Object.keys()` method to get an array of property names and then check if the desired property exists.

Alternatives to Property Access using `hasOwnProperty()`:

* **Using a regex**: You can use a regular expression (e.g., `/a/`) to check if a property exists.
* **Using the `in` operator**: Instead of `hasOwnProperty()`, you can use the `in` operator (e.g., `obj in obj`) to check if an object has a specific property.

Keep in mind that these alternatives may have different performance characteristics and edge cases compared to the approaches tested in this benchmark.

Related benchmarks:

Map vs Object property check (version: 0)

Comparing performance of: obj.hasOwnProperty vs map.get vs obj.a vs map.has

Created: one year ago by: Guest

Jump to the latest result

obj.hasOwnProperty

map.get

obj.a

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):