Benchmark: undefined checks on property in if condition

Script Preparation code:

var obj = {a: 1, b: "b", c: undefined};

Tests:

implicit boolean conversion
if (obj.c) { console.log(obj.c); }
explicit boolean conversion
if (!!obj.c) { console.log(obj.c); }
triple inequality against undefined
if (obj.c !== undefined) { console.log(obj.c); }
typeof
if (typeof obj.c !== "undefined") { console.log(obj.c); }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
implicit boolean conversion
explicit boolean conversion
triple inequality against undefined
typeof

Fastest: N/A

Slowest: N/A

Latest run results:

No previous run results

This benchmark does not have any results yet. Be the first one to run it!

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

LLMs can make mistakes. Check important info.

I'll break down the provided benchmark definition and test cases to explain what's being tested, compare different approaches, and discuss pros and cons.

**Benchmark Definition:**
The benchmark is testing "undefined checks on property in if condition". This means that it measures how browsers handle conditional statements (`if`) when checking for the presence of an undefined value (e.g., `obj.c`).

**Script Preparation Code:**
The script prepares an object `obj` with a property `c` having a value of `undefined`. This is used as input to test various conditional checks.

**Html Preparation Code:**
There's no HTML preparation code provided, so we can assume that the benchmark only focuses on JavaScript execution performance.

**Individual Test Cases:**

1. **Implicit Boolean Conversion:**
	* Benchmark Definition: `if (obj.c) { console.log(obj.c); }`
	* Description: This test case checks how browsers convert an undefined value to a boolean (`false` in this case).
	* Pros: Simple and straightforward.
	* Cons: May not accurately reflect real-world scenarios where explicit conversions are required.
2. **Explicit Boolean Conversion:**
	* Benchmark Definition: `if (!!obj.c) { console.log(obj.c); }`
	* Description: This test case checks how browsers explicitly convert an undefined value to a boolean (`false` in this case).
	* Pros: Provides more control over the conversion process, which might be necessary in certain scenarios.
	* Cons: Can lead to slower execution if unnecessary conversions are required.
3. **Triple Inequality against Undefined:**
	* Benchmark Definition: `if (obj.c !== undefined) { console.log(obj.c); }`
	* Description: This test case checks how browsers compare an undefined value with another value using the triple inequality operator (`!==`).
	* Pros: Provides a more precise way to check for undefined values, especially when working with other types of values.
	* Cons: May be slower than implicit or explicit conversions due to additional comparisons.
4. **typeof:**
	* Benchmark Definition: `if (typeof obj.c !== \"undefined\") { console.log(obj.c); }`
	* Description: This test case checks how browsers use the `typeof` operator to check if a value is undefined.
	* Pros: Provides a way to explicitly check for undefined values, which can be beneficial in certain scenarios.
	* Cons: May lead to slower execution if unnecessary checks are required.

**Other Considerations:**

* The benchmark uses Safari 13 as the test browser. It's essential to note that results may vary when running these tests on different browsers or JavaScript engines.
* The benchmark does not account for edge cases, such as null values or non-object properties.

**Alternatives:**

If you want to explore alternative approaches to this benchmark, consider:

1. Using a more advanced benchmarking framework like WebKit's `Benchmark` API or Microsoft's `Benchmark.js`.
2. Adding additional test cases that cover other aspects of JavaScript conditional statements, such as:
	* Checking for the presence of specific values (e.g., `if (obj.c === 42) { ... }`)
	* Handling errors when checking for undefined values
	* Optimizing performance by reducing the number of checks or using caching

Related benchmarks:

undefined checks on property in if condition (version: 0)

Comparing performance of: implicit boolean conversion vs explicit boolean conversion vs triple inequality against undefined vs typeof

Created: 5 years ago by: Guest

Jump to the latest result

implicit boolean conversion

explicit boolean conversion

triple inequality against undefined

typeof

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):