Benchmark: endswith bad? - MeasureThat.net

Script Preparation code:

var check = "lapKPI"

Tests:

endswith
console.log(!check.endsWith("KPI"))
manual
console.log(check !== "lapKPI" && check !== "runKPI")

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
endswith
manual

Fastest: N/A

Slowest: N/A

Latest run results:

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

LLMs can make mistakes. Check important info.

Let's dive into the explanation of the provided JavaScript benchmark.

**Benchmark Overview**

The MeasureThat.net website allows users to create and run microbenchmarks, which is a way to measure the performance of small code snippets or functions in JavaScript. The benchmark described here tests two different approaches for checking if a string ends with a specific substring.

**Script Preparation Code**

The `Script Preparation Code` specifies that the variable `check` is initialized with the value `"lapKPI"`. This means that both test cases will use this same initial value to check against.

```javascript
var check = "lapKPI";
```

**Options Compared**

There are two test cases:

1. **endswith**: This test case uses the `endsWith()` method of the `String` object, which is a built-in JavaScript method that returns a boolean indicating whether the string ends with the specified substring.
```javascript
console.log(!check.endsWith("KPI"));
```

2. **manual**: This test case uses a manual comparison to check if `check` does not equal `"lapKPI"` and also does not equal `"runKPI"`. This approach is more explicit but can be less efficient due to the additional comparisons.
```javascript
console.log(check !== "lapKPI" && check !== "runKPI");
```

**Pros and Cons of Each Approach**

1. **endsWith() method**:
	* Pros: More concise, readable, and efficient, as it leverages built-in JavaScript functionality.
	* Cons: May not be as explicit or intuitive for some developers who are not familiar with the `endsWith()` method.
2. **Manual comparison**:
	* Pros: More explicit, easier to understand for those unfamiliar with the `endsWith()` method, but potentially less efficient due to additional comparisons.
	* Cons: Less concise and readable, and may be slower than using the built-in method.

**Library**

In this benchmark, there is no explicit library used. However, it's worth noting that some JavaScript engines or browsers might use their own optimizations or algorithms for string manipulation, which could affect the performance of these test cases.

**Special JS Feature/Syntax**

There are no special JavaScript features or syntax mentioned in this benchmark. The code uses standard JavaScript syntax and built-in methods like `endsWith()`.

**Alternative Approaches**

Other approaches to check if a string ends with a specific substring might include:

1. Using a regular expression: `new RegExp('.*KPI$')` or `new RegExp('lapKPI$').test(check)`.
2. Using string slicing and concatenation: `check + 'KPI' === 'lapKPIKPI'`.

However, these alternatives are less common and might not be as efficient or readable as using the built-in `endsWith()` method.

In conclusion, this benchmark tests two different approaches for checking if a string ends with a specific substring in JavaScript. The `endsWith()` method is recommended due to its efficiency, readability, and conciseness.

Related benchmarks:

endswith bad? (version: 0)

Comparing performance of: endswith vs manual

Created: 5 years ago by: Guest

Jump to the latest result

endswith

manual

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):