Benchmark: new Sym vs ++ vs new Arr vs new Obj

Script Preparation code:

var a, b, c, d = Number.MIN_SAFE_INTEGER
var newSym = () => a = Symbol()
var newArr = () => b = []
var newObj = () => c = {}
var pp = () => d++

Tests:

new Sym
newSym()
new Arr
newArr()
new Obj
newObj()
++
pp()

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
new Sym
new Arr
new Obj
++

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/118.0.0.0 Safari/537.36

Browser/OS: Chrome 118 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
new Sym	7091094.0 Ops/sec
new Arr	13185637.0 Ops/sec
new Obj	13208357.0 Ops/sec
++	9020598.0 Ops/sec

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

LLMs can make mistakes. Check important info.

I'll break down the provided benchmark and explain what's being tested, compared, and its pros and cons.

**Benchmark Definition**

The JSON defines a benchmark with four test cases:

1. `newSym()`: Tests creating a new Symbol using the syntax `new Symbol()`.
2. `newArr()`: Tests creating a new Array using the syntax `new []` (which is a shorthand for `new Array(0)`).
3. `newObj()`: Tests creating a new Object using the syntax `new {}`.
4. `pp()`: Tests incrementing a variable using the syntax `++`.

**Library and Special JS Features**

In this benchmark, we don't see any explicit usage of JavaScript libraries like jQuery, Lodash, or React. However, it's worth noting that modern JavaScript engines often use Just-In-Time (JIT) compilation, which can affect performance.

**Increment Operator (`++`)**

The `pp()` test case uses the increment operator (`++`). This is a special feature in JavaScript that increments a variable by 1 and returns the original value. In the context of this benchmark, it's used to increment a counter variable (`d`) until its value reaches `Number.MIN_SAFE_INTEGER`.

**Symbol**

In the `newSym()` test case, a new Symbol is created using the syntax `new Symbol()`. Symbols are unique values that can be used as keys in objects or as properties of other symbols. They're also immutable and have a different behavior compared to strings.

**Array and Object Creation**

The `newArr()` and `newObj()` test cases create new arrays and objects, respectively. These are common data structures in JavaScript, and their creation performance can be an important aspect of benchmarking.

**Comparison of Approaches**

Here's a brief overview of the approaches compared:

*   **`new Sym()` vs `++`**: Creating a new Symbol using `new Symbol()` is likely to be slower than incrementing a variable using `++`. This is because Symbols are unique values that need to be created and stored, which involves additional overhead.
*   **`new Arr()` vs `newObj()`**: Creating an array using `new []` or `new Array(0)` is generally faster than creating an object using `new {}`. This is because arrays are more lightweight and require less overhead compared to objects.

**Pros and Cons**

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

*   **`new Sym()`**:
    *   Pros: Symbols can be used as keys in objects or as properties of other symbols.
    *   Cons: Creating a new Symbol using `new Symbol()` is likely to be slower than incrementing a variable using `++`.
*   **`new Arr()`** and **`newObj()`**:
    *   Pros: These approaches are generally faster and more lightweight compared to creating a new object or symbol.
    *   Cons: Arrays and objects can be less suitable for specific use cases where unique values or keys are required.

**Alternatives**

Some alternative approaches that could be used in this benchmark include:

*   **`const sym = Symbol('symbol-name');`**: This approach creates a new Symbol using the `Symbol()` function with a specified name, which can be faster than creating an empty Symbol.
*   **`var arr = Array(10);`**: This approach creates an array with 10 elements, which can be faster than creating an empty array.

Keep in mind that these alternatives might not change the overall outcome of the benchmark but could provide more accurate results or different insights into the performance characteristics of each approach.

Related benchmarks:

new Sym vs ++ vs new Arr vs new Obj (version: 0)

Comparing performance of: new Sym vs new Arr vs new Obj vs ++

Created: one year ago by: Registered User

Jump to the latest result

new Sym

new Arr

new Obj

++

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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