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padStart vs splice vs loop
(version: 0)
Benchmark.js
Measures speed between using padStart and splice and a pad loop
Comparing performance of:
padStart vs splice vs loop
Created:
4 years ago
by:
Guest
Go to the latest result
Tests:
padStart
let x = 5; let res = ("" + x).padStart(6, "0")
splice
let x = 5; let res = ("0000000" + x).slice(-6)
loop
let x = 5; let res = ''+x while (res.length < 6) { res = '0' + res; }
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (3)
Previous results
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Test case name
Result
padStart
splice
loop
Fastest:
N/A
Slowest:
N/A
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/130.0.0.0 Safari/537.36
Browser/OS:
Chrome 130 on Mac OS X 10.15.7
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Embed Benchmark Result
<iframe src="https://measurethat.net/Embed?id=565945" width="100%" height="500px"></iframe>
splice
64.9M/s
padStart
11.2M/s
loop
10.3M/s
View exact numbers
Test name
Executions per second
✓
splice
64,921,824 Ops/sec
padStart
11,226,049 Ops/sec
loop
10,264,284 Ops/sec
Autogenerated LLM Summary
(model
llama3.2:3b
, generated one year ago):
Let's break down the provided benchmark and its components. **Benchmark Overview** The benchmark measures the performance of three different approaches to pad or manipulate strings in JavaScript: 1. `padStart`: Using the `padStart` method to add leading zeros to a string. 2. `splice`: Using the `splice` method to insert one or more characters at a specified position in a string. 3. A custom "loop" approach, where a while loop is used to concatenate zeros to the end of a string. **Library Used** None of the test cases use any external libraries. **Special JS Features/Syntax** The benchmark uses some special JavaScript features and syntax: * The `padStart` method was introduced in ECMAScript 2017. * The `slice` method was introduced in ECMAScript 2009. However, it's not a string manipulation method like `padStart`, but rather a general-purpose array method that can be used with strings. **Benchmark Approach** The benchmark approach consists of three test cases: 1. **`padStart`**: This test case creates an empty string and pads it with leading zeros using the `padStart` method. 2. **`splice`**: This test case creates an empty string and inserts six zeros at the beginning using the `splice` method (specifically, `-6` as the index). 3. **`loop`**: This test case creates an empty string and concatenates zeros to it in a while loop until its length reaches 6. **Comparison** The benchmark compares the performance of these three approaches: * `padStart`: Uses the `padStart` method, which is likely to be faster since it's optimized for this specific use case. * `splice`: Uses the `splice` method, which may incur additional overhead due to its general-purpose nature and string manipulation requirements. * `loop`: Uses a custom while loop approach, which may have performance characteristics similar to `padStart`, but with more overhead due to the explicit looping. **Pros and Cons** Here are some pros and cons of each approach: * **`padStart`**: + Pros: Optimized for string padding, likely faster execution. + Cons: Requires ECMAScript 2017 support. * **`splice`**: + Pros: General-purpose method with multiple uses. + Cons: May incur additional overhead due to string manipulation requirements. * **`loop`**: + Pros: Custom implementation may be optimized for specific use cases. + Cons: Requires explicit looping, which can lead to performance overhead. **Other Alternatives** Some alternative approaches could have been considered: * Using the `repeat` method (ECMAScript 2015) instead of concatenation in the `loop` test case. * Using a library like Lodash or String-pooling to optimize string manipulation performance. * Experimenting with other string padding methods, such as using `String.fromCharCode` and `Array.prototype.fill`. Keep in mind that these alternatives may not provide significant benefits over the current implementation, and may require additional testing and optimization to achieve noticeable improvements.
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