Benchmark: JSON.parse() vs. eval()

Script Preparation code:

var jsonString = '{"key1": "val1", "key2": 7}'

Tests:

JSON.parse()
var dummy = JSON.parse(jsonString);
eval()
eval('var dummy = ' + jsonString);

Historical Performance Data aggregated from 65 community runs

Desktop Results:

Safari 41 runs

JSON.parse()

2.8M/s

eval()

1.6M/s

Fastest: JSON.parse() (1.7x faster)

View exact numbers

✓ JSON.parse(): 2,817,690 ops/sec
• eval(): 1,610,656 ops/sec

Chrome 24 runs

JSON.parse()

6.0M/s

eval()

2.8M/s

Fastest: JSON.parse() (2.1x faster)

View exact numbers

✓ JSON.parse(): 5,989,886 ops/sec
• eval(): 2,794,544 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
JSON.parse()
eval()

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one month 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

JSON.parse()

2.7M/s

eval()

92K/s

View exact numbers

Test name	Executions per second
✓ JSON.parse()	2,734,574 Ops/sec
eval()	92,394 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 benchmark and explain what's being tested, along with the pros and cons of each approach.

**Benchmark Description**

The benchmark compares the performance of two different methods: `JSON.parse()` and `eval()`. These two functions are used to parse JSON data into JavaScript objects.

**What's being compared?**

* **`JSON.parse()`**: This function is specifically designed to parse JSON data. It's a built-in method in JavaScript that takes a string as input, parses it, and returns a JavaScript object.
* **`eval()`**: This function is used to evaluate a string as JavaScript code. It's not specifically designed for parsing JSON data, but can be used to do so.

**Options compared**

The two options being compared are:

1. `JSON.parse()`: A built-in method in JavaScript that's specifically designed for parsing JSON data.
2. `eval()` : A function that evaluates a string as JavaScript code.

**Pros and Cons of each approach:**

* **`JSON.parse()`**:
	+ Pros:
		- Optimized for performance
		- Specifically designed for parsing JSON data
		- Less chance of security vulnerabilities (since it's a built-in method)
	+ Cons:
		- May not work correctly with malformed or invalid JSON data
* **`eval()`**:
	+ Pros:
		- Can handle more complex JavaScript expressions
	+ Cons:
		- Not optimized for performance
		- More chance of security vulnerabilities (since it's evaluating arbitrary code)
		- Can be slower than `JSON.parse()`

**Library and its purpose**

There is no library being used in this benchmark. However, the `JSON` object is a built-in part of JavaScript.

**Special JS feature or syntax**

The benchmark uses the JSON data format, which is a standardized way of representing data as key-value pairs. This is not specific to any particular JavaScript feature or syntax.

**Other considerations**

When choosing between `JSON.parse()` and `eval()`, it's essential to consider security and performance. If you're working with trusted input data, `JSON.parse()` is usually the better choice. However, if you need to handle untrusted input data or more complex expressions, `eval()` might be necessary.

**Alternatives**

If you don't want to use `JSON.parse()` or `eval()`, you can consider using other JSON parsing libraries or functions, such as:

* `JSON.parse()` alternatives like `json2` or `json-stringify-safe`
* Custom JSON parsing implementations in JavaScript

Keep in mind that these alternatives might have different performance characteristics and security implications.

I hope this explanation helps!

JSON.parse() vs. eval() (version: 0)

Comparing performance of: `JSON.parse() vs eval()`

Created: 7 years ago by: Guest

Go to the latest result

JSON.parse()

eval()

Historical Performance Data aggregated from 65 community runs

Desktop Results:

Safari 41 runs

Chrome 24 runs

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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

JSON.parse() vs. eval() (version: 0)

Comparing performance of: JSON.parse() vs eval()

Created: 7 years ago by: Guest

Go to the latest result

JSON.parse()

eval()

Historical Performance Data aggregated from 65 community runs

Desktop Results:

Safari 41 runs

Chrome 24 runs

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: `JSON.parse() vs eval()`