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Const vs VAR vs LET full
(version: 0)
Const vs VAR vs LET full
Comparing performance of:
Const vs VAR vs LET
Created:
3 years ago
by:
Registered User
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Tests:
Const
const limit = 10000; const A = function (result){ const a = result + 1; if (a < limit){ return A(a); } } A(0)
VAR
var limit = 10000; var A = function (result){ var a = result + 1; if (a < limit){ return A(a); } } A(0)
LET
let limit = 10000; let A = function (result){ let a = result + 1; if (a < limit){ return A(a); } } A(0)
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (3)
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Test case name
Result
Const
VAR
LET
Fastest:
N/A
Slowest:
N/A
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Autogenerated LLM Summary
(model
llama3.2:3b
, generated one year ago):
Let's break down the provided benchmark and explain what's being tested, compared, and their pros/cons. **What is being tested?** The test cases are designed to compare the performance of three different variable declarations in JavaScript: `const`, `var`, and `let`. Each test case defines a recursive function `A` that increments its result until it reaches a predefined limit (`limit`). The tests measure how many times each function executes per second on different browsers. **Options compared** The main options being compared are: 1. **`const`**: A variable declaration that makes the variable immutable, meaning its value cannot be changed after declaration. 2. **`var`**: A variable declaration that is function-scoped and does not declare the variable's scope. 3. **`let`**: A variable declaration that is block-scoped, which means it only has access to the code within its surrounding `let` block. **Pros/Cons of each approach** 1. **`const`**: * Pros: Faster execution times due to constant evaluation and caching by JavaScript engines. * Cons: Variables declared with `const` cannot be reassigned, which might limit its use in certain scenarios. 2. **`var`**: * Pros: Widely supported and compatible across older browsers. * Cons: Slower execution times compared to `const` due to slower variable evaluation and caching. 3. **`let`**: * Pros: Block-scoped, which can improve code readability and maintainability. * Cons: Slower execution times compared to `const`, but only in situations where block scoping is beneficial. **Libraries used** None of the test cases use any external libraries or frameworks that would affect the results. **Special JS feature/syntax** There's no specific JavaScript feature or syntax being tested beyond the variable declarations. However, it's worth noting that this benchmark focuses on the performance differences between `const`, `var`, and `let` due to their scoping behavior. **Other alternatives** If you'd like to explore other variable declaration options in JavaScript, consider: * **`let const`**: A shorter syntax for declaring both variables at once (e.g., `let x = 0; const y = x * 2;`). * **`var with the 'with' statement'**: An older technique that allows you to reuse a variable by creating a new scope using the `with` statement. However, this is not recommended due to performance and compatibility issues. Keep in mind that these alternatives are not being tested in this specific benchmark.
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