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This is an unscientific comparison update from previous blog posts that compared Node and Bun, but didn't compare with Deno.

Temperature conversion

From Converting Celsius to Fahrenheit round-up it compared a super simple script that just prints a couple of lines of text after some basic computation. If you include Deno on that run you get:

❯ hyperfine --shell=none --warmup 3 "bun run conversion.js" "node conversion.js" "deno run conversion.js"
Benchmark 1: bun run conversion.js
  Time (mean ± σ):      22.2 ms ±   2.1 ms    [User: 12.4 ms, System: 8.6 ms]
  Range (min … max):    20.6 ms …  36.0 ms    136 runs

  Warning: Statistical outliers were detected. Consider re-running this benchmark on a quiet system without any interferences from other programs. It might help to use the '--warmup' or '--prepare' options.

...

Summary
  bun run conversion.js ran
    1.97 ± 0.35 times faster than deno run conversion.js
    2.41 ± 0.39 times faster than node conversion.js

My GitHub colleague @joelhawksley recommended a macOS app called MeetingBar.
You installed it and granted it access to your Google Calendar (or Apple Calendar). Now, it can show, in your menu bar, a preview of your next (upcoming) meeting.

I installed it today and it looks like this:

If you click on it, it shows another view of other (next) upcoming events and other all-day events going on.

In the last couple of days, I've created variations of a simple algorithm to demonstrate how Celcius and Fahrenheit seem to relate to each other if you "mirror the number".
It wasn't supposed to be about the programming language. Still, I used Python in the first one and I noticed that since the code is simple, it could be fun to write variants of it in other languages.

1. Converting Celsius to Fahrenheit with Python
2. Converting Celsius to Fahrenheit with TypeScript
3. Converting Celsius to Fahrenheit with Go
4. Converting Celsius to Fahrenheit with Ruby
5. Converting Celsius to Fahrenheit with Crystal
6. Converting Celsius to Fahrenheit with Rust

It was a fun exercise.

UPDATE

See "Run TypeScript in Node without extensions" as of Dec 10, 2024. (5 months later)

You might have heard that Node now has watch mode. It watches the files you're saving and re-runs the node command automatically. Example:

// example.js

function c2f(c) {
  return (c * 9) / 5 + 32;
}
console.log(c2f(0));

Now, run it like this:

❯ node --watch example.js
32
Completed running 'example.js'

Edit that example.js and the terminal will look like this:

Restarting 'example.js'
32
Completed running 'example.js'

(even if the file didn't change. I.e. you just hit Cmd-S to save)

Previously in this series:

1. Converting Celsius to Fahrenheit with Python
2. TypeScript
3. Go
4. Ruby
5. Crystal

This time, in Rust:

fn c2f(c: i8) -> f32 {
    let c = c as f32;
    c * 9.0 / 5.0 + 32.0
}

fn is_mirror(a: i8, b: i8) -> bool {
    let a = massage(a);
    let b = reverse_string(massage(b));
    a == b
}

fn massage(n: i8) -> String {
    if n < 10 {
        return format!("0{}", n);
    } else if n >= 100 {
        return massage(n - 100);
    } else {
        return format!("{}", n);
    }
}

fn reverse_string(s: String) -> String {
    s.chars().rev().collect()
}

fn print_conversion(c: i8, f: i8) {
    println!("{}°C ~= {}°F", c, f);
}

fn main() {
    let mut c = 4;
    while c < 100 {
        let f = c2f(c);
        if is_mirror(c, f.ceil() as i8) {
            print_conversion(c, f.ceil() as i8)
        } else if is_mirror(c, f.floor() as i8) {
            print_conversion(c, f.floor() as i8)
        } else {
            break;
        }
        c += 12;
    }
}

Run it like this:

rustc -o conversion-rs conversion.rs && ./conversion-rs

and the output becomes:

4°C ~= 40°F
16°C ~= 61°F
28°C ~= 82°F
40°C ~= 104°F
52°C ~= 125°F

Previously in this series:

1. Converting Celsius to Fahrenheit with Python
2. TypeScript
3. Go
4. Ruby

Crystal?

Crystal is a general-purpose, object-oriented programming language. With syntax inspired by Ruby, it's a compiled language with static type-checking.

def c2f(c)
    c * 9.0 / 5 + 32;
end

def is_mirror(a, b)
    massage(a).reverse == massage(b)
end

def massage(n)
    if n < 10
        "0#{n}"
    elsif n >= 100
        massage(n - 100)
    else
        n.to_s
    end
end

def print_conv(c, f)
    puts "#{c}°C ~= #{f}°F"
end

(4...100).step(12).each do |c|
    f = c2f(c)
    if is_mirror(c, f.ceil.to_i)
        print_conv(c, f.ceil.to_i)
    elsif is_mirror(c, f.floor.to_i)
        print_conv(c, f.floor.to_i)
    else
        break
    end
end

And this is its diff with the Ruby version:

<     if is_mirror(c, f.ceil)
<         print_conv(c, f.ceil)
<     elsif is_mirror(c, f.floor)
<         print_conv(c, f.floor)
---
>     if is_mirror(c, f.ceil.to_i)
>         print_conv(c, f.ceil.to_i)
>     elsif is_mirror(c, f.floor.to_i)
>         print_conv(c, f.floor.to_i)

Run it like this:

crystal conversion.cr

or build and run:

crystal build -o conversion-cr conversion.cr
./conversion-cr

and the output becomes:

4°C ~= 40°F
16°C ~= 61°F
28°C ~= 82°F
40°C ~= 104°F
52°C ~= 125°F

This is a continuation of Converting Celsius to Fahrenheit with Python, and TypeScript, and Go but in Ruby:

def c2f(c)
    c * 9.0 / 5 + 32;
end

def is_mirror(a, b)
    def massage(n)
        if n < 10
            "0#{n}"
        elsif n >= 100
            massage(n - 100)
        else
            n.to_s
        end
    end
    massage(a).reverse == massage(b)
end

def print_conv(c, f)
    puts "#{c}°C ~= #{f}°F"
end

(4...100).step(12).each do |c|
    f = c2f(c)
    if is_mirror(c, f.ceil)
        print_conv(c, f.ceil)
    elsif is_mirror(c, f.floor)
        print_conv(c, f.floor)
    else
        break
    end
end

Run it like this:

ruby conversion.rb

and the output becomes:

4°C ~= 40°F
16°C ~= 61°F
28°C ~= 82°F
40°C ~= 104°F
52°C ~= 125°F

This is a continuation of Converting Celsius to Fahrenheit with Python, and TypeScript, but in Go:

package main

import (
    "fmt"
    "math"
)

func c2f(c int) float64 {
    return float64(c)*9/5 + 32
}

func isMirror(a int, b int) bool {
    return reverseString(massage(a)) == massage(b)
}

func massage(n int) string {
    switch {
    case n < 10:
        return fmt.Sprintf("0%d", n)
    case n >= 100:
        return massage(n - 100)
    default:
        return fmt.Sprintf("%d", n)
    }
}

func reverseString(s string) string {
    runes := []rune(s)
    for i, j := 0, len(runes)-1; i < j; i, j = i+1, j-1 {
        runes[i], runes[j] = runes[j], runes[i]
    }
    return string(runes)
}

func printConversion(c int, f int) {
    fmt.Println(fmt.Sprintf("%d°C ~= %d°F", c, f))
}

func main() {
    for c := 4; c < 100; c += 12 {
        var f = c2f(c)
        if isMirror(c, int(math.Ceil(f))) {
            printConversion(c, int(math.Ceil(f)))
        } else if isMirror(c, int(math.Floor(f))) {
            printConversion(c, int(math.Floor(f)))
        } else {
            break
        }
    }
}

Run it like this:

go run conversion.go

or build and run:

go build -o conversion-go conversion.go
./conversion-go

and the output becomes:

4°C ~= 40°F
16°C ~= 61°F
28°C ~= 82°F
40°C ~= 104°F
52°C ~= 125°F

This is a continuation of Converting Celsius to Fahrenheit with Python, but in TypeScript:

function c2f(c: number): number {
  return (c * 9) / 5 + 32;
}

function isMirror(a: number, b: number) {
  function massage(n: number) {
    if (n < 10) return `0${n}`;
    else if (n >= 100) return massage(n - 100);
    return `${n}`;
  }
  return reverseString(massage(a)) === massage(b);
}

function reverseString(str: string) {
  return str.split("").reverse().join("");
}

function printConversion(c: number, f: number) {
  console.log(`${c}°C ~= ${f}°F`);
}

for (let c = 4; c < 100; c += 12) {
  const f = c2f(c);
  if (isMirror(c, Math.ceil(f))) {
    printConversion(c, Math.ceil(f));
  } else if (isMirror(c, Math.floor(f))) {
    printConversion(c, Math.floor(f));
  } else {
    break;
  }
}

And when you run it:

❯ bun run conversion.ts
4°C ~= 40°F
16°C ~= 61°F
28°C ~= 82°F
40°C ~= 104°F
52°C ~= 125°F

Here's a useful mnemonic for remembering how to convert Celsius to Fahrenhait(*):

• Start at 4°C
• Add +12 each time
• Flip the C in mirror, with some additional fudging

For example, 4°C is 04°C. Mirror image of "04" is "40". So 4°C equals 40°F.
And when there's a 1 in front, as in 125°F, look at that as 100 + 25°F. Mirror of 25°F is 52°C. So 52°C equals 125°F.

In Python it can be tested like this:

import math


def c2f(c):
    return c * 9 / 5 + 32


def is_mirror(a, b):
    def massage(n):
        if n < 10:
            return f"0{n}"
        elif n >= 100:
            return massage(n - 100)
        else:
            return str(n)

    return massage(a)[::-1] == massage(b)


def print_conv(c, f):
    print(f"{c}°C ~= {f}°F")


for i in range(4, 100, 12):
    f = c2f(i)
    if is_mirror(i, math.ceil(f)):
        print_conv(i, math.ceil(f))
    elif is_mirror(i, math.floor(f)):
        print_conv(i, math.floor(f))
    else:
        break

When you run that you get:

4°C ~= 40°F
16°C ~= 61°F
28°C ~= 82°F
40°C ~= 104°F
52°C ~= 125°F

(*) If you can't remember F = C × 9/5 + 32 or, perhaps, remember it but can't compute the arithmetic easily.