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Array .push() vs .unshift()
(version: 0)
Comparing performance of:
.push() vs .unshift()
Created:
9 years ago
by:
Guest
Go to the latest result
Script Preparation code:
var arr = []
Tests:
.push()
arr.push(42)
.unshift()
arr.unshift(42)
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (2)
Previous results
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Test case name
Result
.push()
.unshift()
Fastest:
N/A
Slowest:
N/A
Latest run results:
Run details:
(Test run date:
one year ago
)
User agent:
Mozilla/5.0 (X11; Linux x86_64; rv:135.0) Gecko/20100101 Firefox/135.0
Browser/OS:
Firefox 135 on Linux
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Embed Benchmark Result
<iframe src="https://measurethat.net/Embed?id=590156" width="100%" height="500px"></iframe>
.push()
16.5M/s
.unshift()
9K/s
View exact numbers
Test name
Executions per second
✓
.push()
16,548,820 Ops/sec
.unshift()
8,693 Ops/sec
Autogenerated LLM Summary
(model
llama3.2:3b
, generated one year ago):
Let's dive into the world of JavaScript microbenchmarks! The provided JSON represents a benchmark test on MeasureThat.net, which compares the performance of two approaches: using the `push()` method versus the `unshift()` method when adding an element to an empty array. **What is being tested?** The test checks how fast each approach can add an element (in this case, the number 42) to an empty array. The `push()` method adds an element to the end of the array, while the `unshift()` method adds an element to the beginning of the array. **Options compared:** There are two options being compared: 1. **`arr.push(42)`**: This is the traditional way to add an element to the end of an array using the `push()` method. 2. **`arr.unshift(42)`**: This approach adds an element to the beginning of the array using the `unshift()` method. **Pros and cons:** * **`arr.push(42)`**: + Pros: - More common and widely used - Easier to implement + Cons: - Can be slower due to the need to shift elements down when adding an element to the end * **`arr.unshift(42)`**: + Pros: - Faster than `push()` because it can avoid shifting elements down + Cons: - Less common and less widely used, which may make it harder for other developers to understand In general, `push()` is a safer choice if you're working with large arrays or need to add elements frequently. However, if you're only adding one element at a time and don't care about performance, `unshift()` might be faster. **Library usage:** There is no library explicitly mentioned in the JSON, but we can assume that the `Array` prototype is being used as intended by both `push()` and `unshift()` methods. These methods are built-in to JavaScript and do not require any external libraries. **Special JS features or syntax:** This benchmark does not use any special JavaScript features or syntax. It only uses standard JavaScript language elements, such as arrays and the `push()` and `unshift()` methods. **Alternative approaches:** If you want to explore alternative approaches for adding elements to an array, here are a few options: 1. **Using `concat()`**: Instead of using `push()` or `unshift()`, you can use the `concat()` method to create a new array with the added element. 2. **Using `slice()` and `Array.prototype.push()`:** You can use `slice()` to extract a subset of an array, push a new element onto it, and then return the resulting array. For example: ```javascript var arr = []; arr = arr.concat(42); ``` or ```javascript var arr = []; arr = arr.slice().concat(42); ``` Keep in mind that these approaches may have different performance characteristics compared to using `push()` or `unshift()`.
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