Benchmark: var vs let vs boolean vs string vs int

Tests:

!! (number)
let a = true
Boolean() (number)
let a = "t"
ternary (number)
let a = 1
!! (string)
var a = true
Boolean() (string)
var a = "t"
ternary (string)
var a = 1

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
!! (number)
Boolean() (number)
ternary (number)
!! (string)
Boolean() (string)
ternary (string)

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 2 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:124.0) Gecko/20100101 Firefox/124.0

Browser/OS: Firefox 124 on Windows

View result in a separate tab

Test name	Executions per second
!! (number)	986763008.0 Ops/sec
Boolean() (number)	984892480.0 Ops/sec
ternary (number)	989451904.0 Ops/sec
!! (string)	989081152.0 Ops/sec
Boolean() (string)	982467200.0 Ops/sec
ternary (string)	984012736.0 Ops/sec

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

LLMs can make mistakes. Check important info.

I'd be happy to explain the test cases and options being compared in the provided benchmark.

**Overview**

The benchmark compares different ways of declaring variables (let, var) and types (boolean, string, number) in JavaScript. The goal is to measure which approach is faster for simple arithmetic operations using the variable values.

**Declaring Variables: let vs var**

The `let` keyword was introduced in ECMAScript 2015 as a new way to declare variables that allows re-declaration of the same variable name within the scope of the block or statement. The `var` keyword, on the other hand, was the traditional way of declaring variables and has some implications:

Pros of `let`:
- Avoids **hoisting**: Variables declared with `let` are not hoisted to the top of their scope, unlike `var`. This means that using `let` can prevent common mistakes like trying to access a variable before it's defined.
- Ensures block scoping: The new scope for variables declared with `let` is introduced only when they are initialized with a value.

Cons of `let`:
- Can't be re-declared in the same scope, unlike `var`.
- May require more code to achieve the desired effect (e.g., using `const` or declaring multiple times).

**Type Declaration: Boolean vs string**

In JavaScript, `true` and `false` are considered as primitive values of type boolean. Strings are also objects that can hold a single value or a sequence of characters.

Pros of using boolean literals (`true`, `false`):
- **Performance**: Comparing boolean values to 0 with `===` is generally faster than comparing strings to an integer literal.
- **Readability**: Boolean literals make the code more readable and easier to understand, as it's clear that `true` represents a true value.

Cons of using boolean literals:
- May not be suitable for all use cases (e.g., when working with string values).

Pros of using string literals (`"t"`):
- Can be used in arithmetic operations.
- Makes the code more readable if you need to work with string values.

Cons of using string literals:
- **Performance**: Comparing strings to an integer literal is generally slower than comparing boolean values to 0.
- May not be suitable for all use cases (e.g., when working with numeric values).

**Other Considerations**

In addition to the options being compared, there are other considerations:

* The `!!` operator: In some browsers, this operator may have different behavior than expected. For example, it can convert non-zero numbers to boolean and vice versa.
* **Browser-specific behavior**: Some JavaScript engines (like Firefox) may have specific optimizations or quirks when dealing with variables and types that might not be immediately apparent.

**Alternatives**

If you're looking for alternative benchmarks or ways to test different aspects of JavaScript, consider the following options:

* V8 Benchmark Suite: A set of benchmarks designed to measure the performance of the V8 engine (used in Google Chrome).
* jsperf.com: An old but still useful benchmarking website for comparing JavaScript engines and libraries.
* Jest or Mocha testing frameworks: Can be used to write and run unit tests, which can help identify performance issues and optimize your code.

Keep in mind that these alternatives might have different focus areas (e.g., focus on performance, security, or specific features) than MeasureThat.net.

Related benchmarks:

var vs let vs boolean vs string vs int (version: 0)

Comparing performance of: !! (number) vs Boolean() (number) vs ternary (number) vs !! (string) vs Boolean() (string) vs ternary (string)

Created: 2 years ago by: Guest

Jump to the latest result

!! (number)

Boolean() (number)

ternary (number)

!! (string)

Boolean() (string)

ternary (string)

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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