Benchmark: Testing for false vs === undefined vs hasOwnProperty for undefined member

Tests:

test truthyness
var n = {}; while (true) { if (!n.foo) break; }
test undefined
var n = {}; var unde = undefined; while (true) { if (n.foo === unde) break; }
test hasOwnProperty
var n = {}; while (true) { if (!n.hasOwnProperty('foo')) break; }

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Suite status: <idle, ready to run>

Previous results

Test case name	Result
test truthyness
test undefined
test hasOwnProperty

Fastest: N/A

Slowest: N/A

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

LLMs can make mistakes. Check important info.

The provided JSON represents a JavaScript benchmark test case on the MeasureThat.net website. The goal of this benchmark is to compare the performance benefits of using different approaches to check if an object property exists or has a certain value.

In this specific benchmark, three individual test cases are defined:

1. `test truthyness`: This test checks the truthiness (i.e., whether it's "truthy" or "falsy") of an object without a `foo` property. The code uses an infinite loop to iterate until the condition is met.
2. `test undefined`: This test checks if a variable (`unde`) is equal to `undefined`. The code uses another infinite loop to find this equality.
3. `test hasOwnProperty`: This test checks if an object has a certain property called "foo". The code again uses an infinite loop to iterate until the condition is met.

Now, let's examine the different approaches used in these tests:

**Approach 1: Using `=== undefined`**

In the `test truthyness` and `test undefined` cases, we see instances of `n.foo === unde`. This approach uses a direct comparison between two values. However, this can be problematic because `=== undefined` will always return false in most modern browsers (since `undefined` is a primitive value), whereas using a logical test like `!n.foo` would.

**Pros:** Simple and straightforward.
**Cons:** May not work as expected due to browser quirks.

**Approach 2: Using a logical test (`!n.foo`)**

In the `test truthyness` case, we see `!n.foo`, which is equivalent to saying "if `foo` does not exist, then exit the loop." This approach is more efficient because it avoids unnecessary comparisons. However, this might be slower for browsers that don't optimize these checks.

**Pros:** More efficient.
**Cons:** May require additional browser support.

**Approach 3: Using `hasOwnProperty`**

In the `test hasOwnProperty` case, we see `!n.hasOwnProperty('foo')`. This approach explicitly checks if an object has a certain property. However, this might be slower than the logical test because it requires more work to check for property existence.

**Pros:** Explicit and easy to understand.
**Cons:** May be slower.

Now, let's consider other alternatives:

* **Using `Object.prototype.hasOwnProperty.call`**: This is another way to check if an object has a certain property. While similar to `hasOwnProperty`, it's slightly more efficient because it avoids the overhead of creating a new `hasOwnProperty` function.
* **Using `in` operator**: Instead of checking for the existence of a property using `hasOwnProperty` or the logical test, you can use the `in` operator (e.g., `n in { foo: null }`). However, this approach has its own quirks and may not work as expected in all cases.

In conclusion, the choice of approach depends on your specific requirements, browser support, and performance considerations. MeasureThat.net's benchmark is designed to help you understand the trade-offs between these different approaches.

Related benchmarks:

Testing for false vs === undefined vs hasOwnProperty for undefined member (version: 0)

Is there a performance benefit to replacing === undefined with a logical test?

Comparing performance of: test truthyness vs test undefined vs test hasOwnProperty

Created: 8 years ago by: Guest

Jump to the latest result

test truthyness

test undefined

test hasOwnProperty

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

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