Benchmark: pre-increment vs post-increment in loops

Script Preparation code:

let i = 0;

Tests:

pre-increment
++i
post-increment
i++
addition assignment operator
i += 1

Historical Performance Data aggregated from 8 community runs

Desktop Results:

Chrome 8 runs

pre-increment

47.8M/s

addition assignment operator

47.8M/s

post-increment

47.4M/s

View exact numbers

✓ pre-increment: 47,797,536 ops/sec
• addition assignment operator: 47,790,836 ops/sec
• post-increment: 47,391,728 ops/sec

Results show median performance across all community submissions. Run this benchmark yourself to verify on your device.

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
pre-increment
post-increment
addition assignment operator

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 19 days ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:152.0) Gecko/20100101 Firefox/152.0

Browser/OS: Firefox 152 on Windows

View result in a separate tab

pre-increment

331.8M/s

post-increment

243.9M/s

addition assignment operator

223.6M/s

View exact numbers

Test name	Executions per second
✓ pre-increment	331,795,936 Ops/sec
post-increment	243,923,520 Ops/sec
addition assignment operator	223,569,152 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 provided JSON and explain what's being tested.

**Benchmark Definition**

The benchmark definition is a simple JavaScript statement that increments a variable `i` by 1. There are three different ways to increment a variable in JavaScript:

*   Pre-increment (`++i`)
*   Post-increment (`i++`)
*   Addition assignment operator (`i += 1`)

These approaches can have different performance implications due to how the JavaScript engine executes them.

**Options Compared**

The benchmark is comparing the execution speed of these three increment operators. Here's a brief overview of each:

*   **Pre-increment (`++i`)**: In this approach, the value of `i` is incremented first, and then the new value is used in the expression. This means that the compiler/interpreter can optimize the code by evaluating the post-increment part before incrementing `i`.
*   **Post-increment (`i++`)**: Here, the expression is evaluated first, and then `i` is incremented. Since the result of the expression is assigned to a new variable (or used in an operation), the compiler/interpreter needs to store the old value of `i` before incrementing it.
*   **Addition assignment operator (`i += 1`)**: In this case, the value of `i` is incremented directly using the addition operator. This approach avoids the need for storing and incrementing `i`, making it potentially faster.

**Pros and Cons**

Here's a brief summary of the pros and cons of each approach:

*   **Pre-increment (`++i`)**: Pros: Can be optimized by the compiler/interpreter. Cons: May have slightly higher overhead due to the need for storing and incrementing `i`.
*   **Post-increment (`i++`)**: Pros: Allows for more flexibility in code usage. Cons: Requires storing and incrementing `i`, which can introduce additional overhead.
*   **Addition assignment operator (`i += 1`)**: Pros: Potentially faster due to reduced overhead from incrementing `i`. Cons: May limit the flexibility of the code.

**Library Used**

None

**Special JS Feature/Syntax**

None (standard JavaScript syntax)

Now, let's discuss alternative approaches:

*   **Using a loop instead of direct increments**: Instead of using pre-increment/post-increment operators, you could use a traditional `for` loop to increment `i`.
*   **Using a different data structure**: Depending on your specific requirements, you might consider using an array or object with indexing to achieve the desired increment behavior.
*   **Profiling and optimization techniques**: You could apply various profiling tools and optimization techniques (e.g., compiler flags, caching) to further optimize the performance of this benchmark.

To run this benchmark in MeasureThat.net, simply fill in the `Script Preparation Code` field with the provided JavaScript code (`let i = 0;`) and set up your test cases according to the individual test case structure.

pre-increment vs post-increment in loops (version: 1)

Comparing performance of: `pre-increment vs post-increment vs addition assignment operator`

Created: 7 years ago by: Registered User

Go to the latest result

pre-increment

post-increment

addition assignment operator

Historical Performance Data aggregated from 8 community runs

Desktop Results:

Chrome 8 runs

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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

pre-increment vs post-increment in loops (version: 1)

Comparing performance of: pre-increment vs post-increment vs addition assignment operator

Created: 7 years ago by: Registered User

Go to the latest result

pre-increment

post-increment

addition assignment operator

Historical Performance Data aggregated from 8 community runs

Desktop Results:

Chrome 8 runs

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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

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Comparing performance of: `pre-increment vs post-increment vs addition assignment operator`