Benchmark: type coercion - MeasureThat.net

Script Preparation code:

var value = undefined;

Tests:

not (!)
!value
truthy (== undefined)
value == undefined
truthy with different type (== null)
value == null
strict equality (=== undefined)
value === undefined

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
not (!)
truthy (== undefined)
truthy with different type (== null)
strict equality (=== undefined)

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 27 days ago):

LLMs can make mistakes. Check important info.

Measuring JavaScript performance is essential for ensuring efficient and scalable codebases. The provided JSON represents a microbenchmarking test, where the focus is on testing type coercion in JavaScript.

**Type Coercion:**

In JavaScript, type coercion occurs when a value is automatically converted to another data type during an operation. This can happen implicitly (e.g., when using operators like `+`, `-`, `==`, or `===`) or explicitly (e.g., when using functions like `Number()` or `String()`).

The benchmark tests different aspects of type coercion:

1. **Negation (`!`)**: Tests the effect of negating a boolean value, which is equivalent to performing a logical NOT operation.
2. **Equality with `undefined` (`== undefined`)**: Compares the truthiness (i.e., whether the value is considered "truthy" or not) of a variable with `undefined`.
3. **Equality with `null` (`== null`)**: Tests the equality comparison between a variable and `null`, which represents the absence of any object value.
4. **Strict Equality with `undefined` (`=== undefined`)**: Checks for strict equality (i.e., both values must be exactly equal, including data type) between a variable and `undefined`.

**Library Usage:**

The benchmark does not explicitly use any libraries beyond JavaScript's built-in functionality.

**Special JS Features/Syntax:**

None are mentioned in the provided JSON. However, it's worth noting that the presence of the exclamation mark (`!`) in some test cases might be relevant to some JavaScript implementations or engines, as it can affect operator precedence and behavior.

**Benchmarking Strategies:**

The benchmark uses a simple preparation code and HTML preparation code (which is empty) to set up the initial state for each test. The raw UA string and browser information indicate that Chrome 112 on a Macintosh device was used to execute these tests.

**Comparison Options:**

There are two primary comparison approaches:

1. **Truthy/Falsey**: `== undefined` and `=== undefined` compare the truthiness of a variable with `undefined`, while `!` performs a negation operation.
2. **Equality vs. Strict Equality**: The latter is more strict, requiring both values to be exactly equal, including data type.

**Pros and Cons:**

* **Truthy/Falsey approach**:
	+ Pros: Simpler to implement, can provide insights into how JavaScript handles truthiness in different contexts.
	+ Cons: May not accurately reflect the behavior of modern JavaScript engines or edge cases where type coercion occurs under specific conditions.
* **Equality vs. Strict Equality**:
	+ Pros: More accurate representation of strict equality checks, which are essential for many use cases (e.g., null checking).
	+ Cons: Can be more complex to implement and may require additional tests to ensure thorough coverage.

**Other Alternatives:**

For comparing different types or evaluating specific JavaScript expressions, other alternatives might include:

* Using a testing framework like Jest or Mocha to write and run custom tests.
* Utilizing the `assert` module in Node.js for assertions and comparisons.
* Implementing manual test cases using a loop, if-else statements, and conditional logic.

Keep in mind that this is just a basic explanation of the provided benchmark. Depending on your specific use case or requirements, you may need to explore additional approaches or libraries to ensure accurate performance testing results.

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/112.0.0.0 Safari/537.36

Browser/OS: Chrome 112 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
not (!)	34999480.0 Ops/sec
truthy (== undefined)	12132405.0 Ops/sec
truthy with different type (== null)	34988168.0 Ops/sec
strict equality (=== undefined)	12187984.0 Ops/sec

Related benchmarks:

type coercion (version: 0)

Comparing performance of: not (!) vs truthy (== undefined) vs truthy with different type (== null) vs strict equality (=== undefined)

Created: one year ago by: Guest

Jump to the latest result

not (!)

truthy (== undefined)

truthy with different type (== null)

strict equality (=== undefined)

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 27 days ago):