Benchmark: JSON.parse() vs. eval() large object 2

Script Preparation code:

var jsonString = '{"user":{"id":1,"name":{"first":"太郎","last":"山田"},"age":30,"email":"taro.yamada@example.com","address":{"street":"1-2-3","city":"東京","prefecture":"東京都","postalCode":"100-0001"},"phoneNumbers":[{"type":"mobile","number":"090-1234-5678"},{"type":"home","number":"03-1234-5678"}],"hobbies":[{"name":"サッカー","level":"中級"},{"name":"読書","genres":["フィクション","ノンフィクション","ミステリー"]},{"name":"料理","skills":{"cuisine":["和食","イタリアン"],"level":"上級"}}],"preferences":{"language":"日本語","notifications":{"email":true,"sms":false,"push":true}}}}'
var jsonString2 = '({"user":{"id":1,"name":{"first":"太郎","last":"山田"},"age":30,"email":"taro.yamada@example.com","address":{"street":"1-2-3","city":"東京","prefecture":"東京都","postalCode":"100-0001"},"phoneNumbers":[{"type":"mobile","number":"090-1234-5678"},{"type":"home","number":"03-1234-5678"}],"hobbies":[{"name":"サッカー","level":"中級"},{"name":"読書","genres":["フィクション","ノンフィクション","ミステリー"]},{"name":"料理","skills":{"cuisine":["和食","イタリアン"],"level":"上級"}}],"preferences":{"language":"日本語","notifications":{"email":true,"sms":false,"push":true}}}})'

Tests:

JSON.parse()
var dummy = JSON.parse(jsonString);
eval()
var dummy = eval(jsonString2);

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:148.0) Gecko/20100101 Firefox/148.0

Browser/OS: Firefox 148 on Windows

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Test name	Executions per second
JSON.parse()	310856.7 Ops/sec
eval()	256891.3 Ops/sec

Autogenerated LLM Summary (model gpt-4o-mini, generated one year ago):

LLMs can make mistakes. Check important info.

The benchmark presented compares two different methods for parsing a JSON-like string in JavaScript: `JSON.parse()` and `eval()`.

### Approaches Compared:

1. **JSON.parse()**
   - **Definition**: A built-in JavaScript function that parses a JSON string and constructs the corresponding JavaScript value or object.
   - **Test Code**: `var dummy = JSON.parse(jsonString);`
   - **Pros**:
     - **Security**: `JSON.parse()` is inherently safer as it does not execute any JavaScript code contained in the string. This makes it less vulnerable to code injection attacks.
     - **Performance**: Optimized for parsing valid JSON, providing better performance for typical JSON structures compared to `eval()`.
     - **Validity**: It only accepts valid JSON syntax, meaning malformed JSON strings will throw an error, helping to catch errors early.
   - **Cons**:
     - **Limited to JSON**: It can only parse strings formatted as JSON, which may not be flexible for certain non-JSON-like structures.

2. **eval()**
   - **Definition**: A JavaScript function that evaluates a string as JavaScript code.
   - **Test Code**: `var dummy = eval(jsonString2);`
   - **Pros**:
     - **Flexibility**: Since `eval()` executes the string as JavaScript code, it can handle any JavaScript expression, not just valid JSON.
   - **Cons**:
     - **Security Risks**: Using `eval()` poses significant security risks as it can execute potentially harmful code if the input string is derived from an untrusted source.
     - **Performance**: Generally slower than `JSON.parse()` for parsing JSON as it has to invoke the JavaScript interpreter and execute the code, which adds overhead.
     - **Debugging Difficulty**: Errors in evaluated code can be harder to track down.

### Libraries and Features Involved:
- **JSON Object**: Part of the JavaScript language, which provides methods for working with JSON, including serialization (`JSON.stringify()`) and parsing (`JSON.parse()`).
- The benchmark does not use any external libraries; it relies solely on built-in JavaScript functionality.
  
### Considerations:
- **Use Case**: Developers should generally prefer `JSON.parse()` for parsing JSON due to its safety, performance, and clarity. `eval()` might only be considered in very specific contexts where dynamic execution of JavaScript is required, and the input can be trusted.
- **Browser Compatibility**: Both approaches are widely supported across all modern browsers, though performance may vary based on the JavaScript engine in each browser.
  
### Alternatives:
- **Third-Party Libraries**: For more advanced JSON operations or to enhance performance, libraries like `lodash` can be used, though they typically do not replace `JSON.parse()`. `lodash` can handle deep cloning, merging, and other data transformations which extend beyond simple parsing.
- **Structured Clone**: If your goal is to clone complex objects, using the structured clone algorithm (available in Web APIs but not directly in JavaScript) may be appropriate, especially for non-JSON serializable structures.

In summary, for typical JSON parsing tasks, `JSON.parse()` is the recommended approach due to its security, performance, and consistency, while `eval()` should be avoided unless absolutely necessary and only with trusted input.

Related benchmarks:

JSON.parse() vs. eval() large object 2 (version: 1)

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

Created: one year ago by: Guest

Jump to the latest result

JSON.parse()

eval()

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model gpt-4o-mini, generated one year ago):