Benchmark: JSON.parse vs string.split for numbers

Script Preparation code:

var array = new Array(5000).fill('1').map(() => Math.random());
var strJson = JSON.stringify(array);
var strComma = array.join(',');

Tests:

JSON.parse
JSON.parse(strJson);
String.split
strComma.split(',').map(Number)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
JSON.parse
String.split

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 6 days ago)

User agent: Mozilla/5.0 (iPhone; CPU iPhone OS 18_1 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) GSA/346.1.704810410 Mobile/15E148 Safari/604.1

Browser/OS: Mobile Safari 18 on iOS 18.1

View result in a separate tab

Test name	Executions per second
JSON.parse	2886.6 Ops/sec
String.split	2013.4 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks!

The provided JSON represents a benchmark test between two approaches: `JSON.parse` and `string.split` for parsing an array of numbers.

**What is being tested?**

Two options are compared:

1. **JSON.parse**: This method parses a JSON string into a JavaScript object.
2. **String.split**: This method splits a string into an array of substrings using a specified separator (in this case, the comma).

The test creates an array of 5000 numbers with random values, converts it to a JSON string (`strJson`), and then compares the execution times of:

* Parsing the JSON string using `JSON.parse`
* Splitting the string into an array using `string.split`

**Options compared:**

* **Speed**: Which method is faster?
	+ Pro: If one method is significantly faster, it's better to use that approach.
	+ Con: If both methods are comparable in performance, it may not be worth optimizing for one over the other.
* **Readability and maintainability**: How easy is it to understand and work with each approach?
	+ Pro: `JSON.parse` can be more readable and concise for parsing JSON data.
	+ Con: `String.split` can be less intuitive for parsing arrays of numbers.

**Library and purpose:**

In this test, the `JSON` object is used as a library to parse the JSON string. The `JSON.stringify()` method is also part of the JavaScript standard library, but it's not explicitly mentioned in the benchmark definition.

**Special JS feature or syntax:**

There are no special features or syntaxes being tested in this benchmark.

**Other alternatives:**

If you were to modify this test, other approaches you could consider include:

* **Using a loop**: Instead of `JSON.parse`, use a simple loop to parse each number in the array.
* **Using a library like Lodash**: Consider using a library like Lodash, which provides utility functions for working with arrays and objects.

Here's an example of how you could modify the benchmark definition to include these alternatives:

```json
"[
    {
        "Benchmark Definition": "for (var i = 0; i < array.length; i++) { result[i] = array[i]; }"
    },
    {
        "Benchmark Definition": "_.map(array, Number)"
    }
]"
```

This would add two more test cases to the benchmark: using a loop to parse each number in the array and using Lodash's `map()` function to parse the numbers.

Related benchmarks:

JSON.parse vs string.split for numbers (version: 0)

This shows that JSON.parse can be faster than str.split

Comparing performance of: JSON.parse vs String.split

Created: 10 months ago by: Guest

Jump to the latest result

JSON.parse

String.split

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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