Benchmark: Memory Usage - MeasureThat.net

Script Preparation code:

window.x = { a: 1 };

Tests:

undefined
x.a = undefined;
delete
delete x.a;

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
undefined
delete

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/136.0.0.0 Safari/537.36

Browser/OS: Chrome 136 on Windows

View result in a separate tab

Test name	Executions per second
undefined	131898568.0 Ops/sec
delete	81634360.0 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 data.

**Overview**
The benchmark measures the memory usage of JavaScript variables when assigned new values. It specifically tests the behavior of `undefined`, `delete` statements, and variable assignments with no initial value.

**Benchmark Definition**
The benchmark definition is a simple assignment statement that creates an object `x` with a property `a`. The `Script Preparation Code` section provides an initial state by setting `window.x = { a: 1 };`. This means the test starts with a variable `x` having a value of `{ a: 1 }`.

**Options Compared**
There are two options being compared:

1. **Undefined**: The first test case assigns `undefined` to `x.a`. This tests how JavaScript handles the assignment of `undefined` to a property.
2. **Delete**: The second test case uses the `delete` operator to delete the property `a` from the object `x`.

**Pros and Cons**

*   **Undefined:**
    *   Pros:
        *   Simplifies understanding of variable assignments in JavaScript
        *   Easy to implement and understand
    *   Cons:
        *   May not accurately reflect real-world scenarios where variables are initialized with a specific value or type
        *   Can be misleading if the test is run on systems where garbage collection happens immediately after assignment, potentially hiding the impact of the `undefined` assignment.
*   **Delete:**
    *   Pros:
        *   More representative of common JavaScript usage patterns (e.g., clearing data from an object or array)
        *   Can help identify performance issues related to memory management and variable deallocation
    *   Cons:
        *   May require additional setup or handling to ensure the test is run in a state where `delete` has no unintended side effects

**Other Considerations**

*   The benchmark doesn't account for caching, which might influence the results. In some browsers, assigning an object with a specific property can cause it to be cached and reused instead of being created anew.
*   The `window.x = {a: 1};` setup is used to initialize `x.a`. This means that if you were running this test multiple times consecutively without resetting the variable, `x.a` would retain its value from previous runs. This could lead to inconsistent results and might not accurately represent real-world usage patterns.

**Library Usage**
The benchmark doesn't explicitly use any libraries. However, it relies on the browser's JavaScript engine and its built-in features like `delete`. The test is designed to work with a basic understanding of JavaScript syntax and semantics.

**Special JS Features or Syntax**
There are no special features or syntaxes being tested in this benchmark. The code is straightforward and only uses standard JavaScript assignment operators and the `delete` operator.

**Alternatives**
If you were interested in exploring different approaches, some alternatives could include:

*   Creating multiple test cases to explore various scenarios (e.g., assigning objects with specific properties or values)
*   Using a more complex object structure to evaluate memory usage during variable assignments
*   Integrating this benchmark into a larger suite of tests that assess the performance and behavior of different JavaScript engines under various conditions

Related benchmarks:

Memory Usage (version: 0)

Comparing performance of: undefined vs delete

Created: 6 years ago by: Guest

Jump to the latest result

undefined

delete

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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