Benchmark: Map vs Object hasOwnProperty and others

Script Preparation code:

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

Tests:

Map lookup
for (i = 0; i < count; i++) { a = map.get('a'); }
Obj lookup
for (i = 0; i < count; i++) { a = obj['a']; }
Obj hasOwnProperty lookup
for (i = 0; i < count; i++) { a = obj.hasOwnProperty('a'); }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Map lookup
Obj lookup
Obj hasOwnProperty lookup

Fastest: N/A

Slowest: N/A

Latest run results:

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

LLMs can make mistakes. Check important info.

Let's break down what is being tested in this benchmark.

**Overview**
The benchmark compares the performance of three different approaches to access a value in a JavaScript object: `map.get()`, `obj['a']` (property access), and `obj.hasOwnProperty('a')`.

**Benchmark Definition JSON**

The benchmark definition includes:

* **Script Preparation Code**: This code sets up two variables, `map` and `obj`, which are initialized as empty Map and object respectively. It then adds a key-value pair to both the map and the object.
* **Html Preparation Code**: This field is empty, indicating that no HTML preparation is required for this benchmark.

**Individual Test Cases**

There are three test cases:

1. **Map Lookup**: The script runs a loop `count` times, accessing the value associated with the key `'a'` in the `map` object using the `get()` method.
2. **Object Lookup**: The script runs a loop `count` times, accessing the value associated with the key `'a'` in the `obj` object using the square bracket notation (`obj['a']`).
3. **Object hasOwnProperty Lookup**: The script runs a loop `count` times, checking if the `obj` object has a property named `'a'` using the `hasOwnProperty()` method.

**Library and Special JavaScript Features**

None of these test cases use any external libraries. However, it's worth noting that the `Map` data structure is a built-in JavaScript feature introduced in ECMAScript 2015 (ES6).

**Approach Comparison**

The three approaches differ in their syntax and implementation:

* **Map Lookup**: Uses the `get()` method of the `map` object to access the value. This approach is generally faster than property access because it uses a hash table lookup, which has an average time complexity of O(1).
* **Object Lookup**: Uses the square bracket notation (`obj['a']`) to access the value. This approach is slower than `map.get()` because it involves a string search and then a lookup in the object's property map.
* **Object hasOwnProperty Lookup**: Uses the `hasOwnProperty()` method of the `obj` object to check if it has a property named `'a'`. While this approach may seem similar to property access, it actually performs an additional step by checking if the property is an own property (i.e., not inherited from the prototype chain).

**Pros and Cons**

* **Map Lookup**: Pros: fast, efficient, and straightforward. Cons: requires a `Map` object, which might not be available in all environments.
* **Object Lookup**: Pros: widely supported, easy to implement. Cons: slower than `map.get()`, may involve additional steps due to string search.
* **Object hasOwnProperty Lookup**: Pros: checks for ownership of property, avoiding inherited properties. Cons: slower and more complex than direct property access.

**Other Alternatives**

If you need to perform a lookup on an object or a map in JavaScript, some other alternatives include:

* Using the `in` operator or the `has()` method on the prototype chain.
* Creating a custom lookup function using a combination of string search and array indexing.
* Using a library like Lodash or Ramda for more advanced data manipulation and filtering tasks.

Keep in mind that the choice of approach depends on the specific requirements and constraints of your use case.

Related benchmarks:

Map vs Object hasOwnProperty and others (version: 0)

Lookup of map vs object

Comparing performance of: Map lookup vs Obj lookup vs Obj hasOwnProperty lookup

Created: 3 years ago by: Guest

Jump to the latest result

Map lookup

Obj lookup

Obj hasOwnProperty lookup

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

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