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let vs const v1
(version: 0)
Benchmark.js
Comparing performance of:
let vs const
Created:
2 years ago
by:
Guest
Go to the latest result
Script Preparation code:
function send_nodeagg(aggr) { return aggr.get('key')}
Tests:
let
let nagg = new Map(); let nodeagg = {aggr: nagg, send: send_nodeagg, currdt: '', currhost: '', currmap: new Map()}; nodeagg.send(nodeagg.aggr);
const
const nagg = new Map(); const nodeagg = {aggr: nagg, send: send_nodeagg, currdt: '', currhost: '', currmap: new Map()}; nodeagg.send(nodeagg.aggr);
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (2)
Previous results
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Test case name
Result
let
const
Fastest:
N/A
Slowest:
N/A
Latest run results:
Run details:
(Test run date:
2 years ago
)
User agent:
Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/118.0.0.0 Safari/537.36
Browser/OS:
Chrome 118 on Linux
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Embed Benchmark Result
<iframe src="https://measurethat.net/Embed?id=508108" width="100%" height="500px"></iframe>
const
4.1M/s
let
4.1M/s
View exact numbers
Test name
Executions per second
✓
const
4,147,894 Ops/sec
let
4,108,725 Ops/sec
Autogenerated LLM Summary
(model
llama3.2:3b
, generated one year ago):
Let's dive into the world of JavaScript microbenchmarks on MeasureThat.net. **Benchmark Overview** The provided benchmark measures the performance difference between using `let` and `const` in JavaScript, specifically when creating objects with nested properties. The test case creates an object `nodeagg` that contains a map (`nagg`) and calls a function `send_nodeagg` on it. **Options Compared** Two options are being compared: 1. **Let**: The first option uses the `let` keyword to declare the `nagg` variable, which is then used as part of an object. 2. **Const**: The second option uses the `const` keyword to declare the `nagg` variable, which is also used as part of an object. **Pros and Cons** * **Let**: When using `let`, JavaScript resolves the reassignment issue by always declaring a new variable when assigning a value to it. This means that if you assign a new value to `nagg` later on in your code, a new map will be created. However, this can lead to performance implications due to the overhead of creating a new object. * **Const**: When using `const`, JavaScript also resolves the reassignment issue by declaring a constant variable when assigning a value to it. This means that once a value is assigned to `nagg`, it cannot be reassigned to, and any subsequent updates will modify the original map. However, this can lead to limitations in flexibility when working with data structures. **Library and Purpose** In the benchmark preparation code, the following library is used: * `Map`: A JavaScript object that preserves the order of insertion, allowing for efficient key-value pair lookups. * `send_nodeagg` function: This function takes an argument (`aggr`) which is expected to be a Map. It returns the value of this map using the `get()` method. **Special JS Feature/Syntax** There is no special JavaScript feature or syntax being used in this benchmark that would affect its execution or interpretation. **Other Alternatives** Other alternatives for this benchmark could include: * Using `var` instead of `let` and `const`, which would also declare a variable but with different scope and reassignment rules. * Creating objects using array literals (`[]`) or object literals (`{}`) instead of maps, to test performance characteristics related to these data structures. * Adding additional operations or complexity to the `send_nodeagg` function or the object creation process to simulate real-world scenarios. In conclusion, this benchmark measures the performance difference between using `let` and `const` when creating objects with nested properties. The results highlight the reassignment implications of each keyword, which can impact performance in certain cases.
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