Benchmark: Object look-up - MeasureThat.net

Script Preparation code:

var withPrototype = {};
var withoutPrototype = Object.create(null);

for (var i=0; i<100; ++i) {
  withPrototype[i] = true;
  withoutPrototype[i] = true;
}

var hasOwnProperty = Object.prototype.hasOwnProperty;

Tests:

access property with prototype
for (var i=0; i<100; ++i) { if (withPrototype[i]) continue; }
access property without prototype
for (var i=0; i<100; ++i) { if (withoutPrototype[i]) continue; }
in with prototype
for (var i=0; i<100; ++i) { if (i in withPrototype) continue; }
in without prototype
for (var i=0; i<100; ++i) { if (i in withoutPrototype) continue; }
hasOwnProperty with prototype
for (var i=0; i<100; ++i) { if (hasOwnProperty.call(withPrototype, i)) continue; }
hasOwnProperty without prototype
for (var i=0; i<100; ++i) { if (hasOwnProperty.call(withoutPrototype, i)) continue; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
access property with prototype
access property without prototype
in with prototype
in without prototype
hasOwnProperty with prototype
hasOwnProperty without prototype

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (X11; CrOS x86_64 14541.0.0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/126.0.0.0 Safari/537.36

Browser/OS: Chrome 126 on Chrome OS 14541.0.0

View result in a separate tab

in with prototype

3.2M/s

access property with prototype

3.2M/s

in without prototype

2.7M/s

access property without prototype

2.7M/s

hasOwnProperty without prototype

637K/s

hasOwnProperty with prototype

595K/s

View exact numbers

Test name	Executions per second
✓ in with prototype	3,225,178 Ops/sec
access property with prototype	3,197,786 Ops/sec
in without prototype	2,682,230 Ops/sec
access property without prototype	2,659,142 Ops/sec
hasOwnProperty without prototype	636,502 Ops/sec
hasOwnProperty with prototype	595,494 Ops/sec

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

LLMs can make mistakes. Check important info.

**Overview of Object Look-up Benchmark**

The Object Look-up benchmark is designed to measure the performance of JavaScript engines in accessing properties on objects, both with and without prototypes. The test cases simulate a common use case where an object's property is checked, and if it exists, its value is accessed.

**Benchmark Definition JSON Analysis**

The provided JSON defines two types of objects:

1. `withPrototype`: An object created using the `Object.create(null)` method, which inherits from the `null` prototype chain.
2. `withoutPrototype`: An object created using the same method as above, but without any prototype inheritance.

Two arrays are populated with properties on these objects: one using a `for` loop and the other using the `in` operator or the `hasOwnProperty` method.

**Test Cases Analysis**

There are six test cases:

1. **access property with prototype**: Verifies that accessing a property on an object with a prototype throws a TypeError.
2. **access property without prototype**: Verifies that accessing a property on an object without a prototype throws a TypeError.
3. **in with prototype**: Verifies that the `in` operator works correctly when used with an object and its prototype chain.
4. **in without prototype**: Verifies that the `in` operator throws a TypeError when used with an object without a prototype chain.
5. **hasOwnProperty with prototype**: Verifies that calling `hasOwnProperty` on an object returns true if the property exists, even with a prototype chain.
6. **hasOwnProperty without prototype**: Verifies that calling `hasOwnProperty` on an object returns false if the property does not exist.

**Options Comparison**

There are two main options:

1. **Using the `in` operator**: This option uses the `in` operator to check if a property exists on an object.
2. **Using the `hasOwnProperty` method**: This option calls the `hasOwnProperty` method on the `Object.prototype` or the object itself.

**Pros and Cons**

* Using the `in` operator:
	+ Pros: Fast, efficient, and widely supported across browsers.
	+ Cons: May not work correctly with some legacy code or complex inheritance scenarios.
* Using the `hasOwnProperty` method:
	+ Pros: More explicit and intuitive than the `in` operator, especially for developers familiar with the method.
	+ Cons: May be slower due to additional overhead, especially in older browsers.

**Library and Purpose**

The `Object.create(null)` method is a standard JavaScript method used to create an object without any prototype inheritance. The `hasOwnProperty` method is also a standard property on the `Object.prototype`, which checks if a property exists only on that specific object's property chain.

**Special JavaScript Features or Syntax**

This benchmark does not use any special JavaScript features or syntax, but it is worth noting that some older browsers may have different behavior for certain features, such as the `in` operator or `hasOwnProperty`.

**Other Alternatives**

There are other benchmarks and test cases available to measure similar performance characteristics, such as:

* V8 Benchmark Suite: A comprehensive benchmark suite developed by Google for measuring JavaScript engine performance.
* jsPerf: A benchmarking tool for JavaScript that allows users to create and run custom benchmarks.

By analyzing these alternatives, developers can gain a deeper understanding of the performance characteristics of different JavaScript engines and optimize their code accordingly.

Object look-up (version: 0) Benchmark.js

Comparing performance of: `access property with prototype vs access property without prototype vs in with prototype vs in without prototype vs hasOwnProperty with prototype vs hasOwnProperty without prototype`

Created: 9 years ago by: Guest

Go to the latest result

access property with prototype

access property without prototype

in with prototype

in without prototype

hasOwnProperty with prototype

hasOwnProperty without prototype

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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

Object look-up (version: 0) Benchmark.js

Comparing performance of: access property with prototype vs access property without prototype vs in with prototype vs in without prototype vs hasOwnProperty with prototype vs hasOwnProperty without prototype

Created: 9 years ago by: Guest

Go to the latest result

access property with prototype

access property without prototype

in with prototype

in without prototype

hasOwnProperty with prototype

hasOwnProperty without prototype

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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

Related benchmarks

Comparing performance of: `access property with prototype vs access property without prototype vs in with prototype vs in without prototype vs hasOwnProperty with prototype vs hasOwnProperty without prototype`