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void 0 and undefined in deep call stack - 5
(version: 0)
Benchmark.js
Check performance degradation due to scope chain when undefined is called from deep stack
Comparing performance of:
a == undefined vs a == void 0
Created:
2 years ago
by:
Guest
Go to the latest result
Tests:
a == undefined
function compare(n= 1e3){ let a = undefined; for(let i = 0; i < n; i++){ a === undefined; } } function deep(num){ if (num === 0) { compare(); return; } else { deep(num-1); } } deep(1);
a == void 0
function compare(n= 1e3){ let a = undefined; for(let i = 0; i < n; i++){ a === void 0; } } function deep(num){ if (num === 0) { compare(); return; } else { deep(num-1); } } deep(1);
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (2)
Previous results
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Test case name
Result
a == undefined
a == void 0
Fastest:
N/A
Slowest:
N/A
Latest run results:
Run details:
(Test run date:
2 years ago
)
User agent:
Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36
Browser/OS:
Chrome 120 on Mac OS X 10.15.7
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<iframe src="https://measurethat.net/Embed?id=500359" width="100%" height="500px"></iframe>
a == void 0
1.9M/s
a == undefined
19K/s
View exact numbers
Test name
Executions per second
✓
a == void 0
1,876,525 Ops/sec
a == undefined
18,882 Ops/sec
Autogenerated LLM Summary
(model
llama3.2:3b
, generated one year ago):
Let's break down the provided benchmark JSON and explain what's being tested. **Benchmark Definition** The benchmark definition provides two script files that are used to create test cases: 1. `compare.js`: This script defines a function `compare` that checks if `a` is equal to `undefined`. The function loops `n` times, where `n` is set to 10^3 (1000) by default. 2. `deep.js`: This script defines a recursive function `deep` that calls itself with decreasing values of `num` until it reaches 0. When `num` is 0, the `compare` function is called. **Test Cases** There are two test cases defined in the JSON: 1. "a == undefined" * This test case uses the `compare.js` script and checks if the `compare` function takes longer to execute when comparing `undefined` instead of `void 0`. 2. "a == void 0" * This test case uses the `deep.js` script, which creates a deep call stack by recursively calling itself with decreasing values of `num`. The comparison is done using `===` operator. **Options Compared** The two test cases compare the performance of comparing `undefined` and `void 0` in different contexts: * In the first test case (`"a == undefined"`), the focus is on the scope chain when calling `compare` from a deep stack. * In the second test case (`"a == void 0"`), the focus is on the performance of recursive function calls and comparisons using `===` operator. **Pros and Cons** Here are some pros and cons of each approach: 1. "a == undefined" * Pros: This test case focuses on a specific scenario where scope chain matters, making it easier to identify performance issues related to this aspect. * Cons: The test case might not accurately represent real-world usage, as `undefined` is often used in conditional statements rather than comparisons. 2. "a == void 0" * Pros: This test case covers a more general scenario that reflects common use cases for comparing values using `===`. * Cons: The recursive function calls and comparisons might not accurately represent real-world performance issues. **Libraries and Special JS Features** None of the provided script files use any external libraries. However, some JavaScript features like arrow functions (`=>`) are used in the code. **Other Considerations** When running these benchmarks, it's essential to consider the following: * Browser rendering: Some browsers might have different performance characteristics due to rendering engines and memory management. * Hardware-specific optimizations: Different hardware configurations (e.g., Intel vs. ARM-based devices) can impact performance due to varying instruction sets and caching mechanisms. **Alternatives** If you wanted to create alternative benchmark test cases, consider the following: 1. Use `Object.prototype.hasOwnProperty.call` instead of `===` for comparison. 2. Compare the performance of comparing values using `===` vs. `==`. 3. Test the impact of scope chain on performance in different contexts (e.g., function calls, loops). 4. Create a benchmark that measures the performance of recursive functions with varying levels of recursion. By exploring alternative test cases and considerations, you can gain a deeper understanding of the performance implications of JavaScript code and optimize your applications accordingly.
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