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undefined vs void 0
(version: 0)
Comparing performance of:
undefined vs void 0
Created:
4 years ago
by:
Guest
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Tests:
undefined
var a = 999; for(var i = 0; i < 10000;i++) { a = undefined; }
void 0
var a = 999; for(var i = 0; i < 10000;i++) { a = void 0; }
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (2)
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Test case name
Result
undefined
void 0
Fastest:
N/A
Slowest:
N/A
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Autogenerated LLM Summary
(model
llama3.2:3b
, generated one year ago):
Let's break down the provided benchmark and explain what's being tested, compared, and the pros and cons of each approach. **What's being tested:** The test case compares two ways to assign `undefined` or `void 0` to a variable `a`. The first test case uses `undefined`, while the second test case uses `void 0`. **Options being compared:** 1. **Using `undefined`:** This is an older way of assigning `undefined` in JavaScript, which was used before the introduction of `void 0`. 2. **Using `void 0`:** Introduced in ECMAScript 5 (2015), `void 0` is a more modern and concise way to assign `undefined`. It's equivalent to `undefined`, but with improved performance. **Pros and Cons:** * **Using `undefined`:** + Pros: Widely supported by older browsers, easier to read for those familiar with the syntax. + Cons: May be slower due to the need for explicit type conversion. * **Using `void 0`:** + Pros: Faster execution speed, more modern and concise syntax. + Cons: Requires a newer JavaScript engine that supports ECMAScript 5. **Library usage:** There are no libraries being used in this benchmark. The test case is purely focused on comparing the performance of these two ways to assign `undefined`. **Special JS feature or syntax:** None, as this is a basic comparison without any advanced features or syntax specific to modern JavaScript. **Other alternatives:** In theory, other methods to assign `undefined` could be used, such as: * `null` * `undefined` (as in the test case) * `void 0` (the more modern and recommended approach) However, these alternatives are not being compared in this specific benchmark. Overall, this benchmark is designed to highlight the performance difference between two ways of assigning `undefined`, with a focus on the newer `void 0` syntax.
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