When it comes to formatting time into the human-readable format in Rust, there could be various possible solutions including doing some math or using Instance. However, I demonstrate the millisecond crate, the dedicated and specialized crate for the purpose. This crate converts nanoseconds, microseconds, milliseconds, seconds, etc into short and long formats; suitable for human eyes.

Imagine we have a variable containing a milliseconds value like 33023448000, computed somewhere in our code, and we want to show users the tangible equivalent result like 1 year 17 days 5 hours 10 minutes 48 seconds or a compact version 1y 17d 5h 10m 48s. Here the millisecond crate plays its role.

Project setup

First, ensure you have installed Rust and Cargo on your system and they are available in Terminal (CMD on Windows).

1. Create project

Run the following command to initialize an empty binary project:

cargo init my-millisecond --bin && cd my-millisecond

2. Install millisecond crate

At the moment, the latest version of the crates is 0.3.

cargo add millisecond@0.3

3. Use the crate

Open src/main.rs and write the following code:

use millisecond::Millisecond;

fn main() {
    let computed_millis = 33023448000;
    let ms = Millisecond::from_millis(computed_millis);
    println!("{ms}"); // results in: 1y 17d 5h 10m 48s
}

4. Run the project

cargo run

output:

~/my-millisecond$ cargo run
   Compiling my-millisecond v0.1.0 (~/my-millisecond)
    Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.19s
     Running `target/debug/my-millisecond`
1y 17d 5h 10m 48s

I used the default formatting function (Display) in the example. You can use the strict method of ms.to_short_string() instead, or use ms.to_long_string() to print the long version of the output.

use millisecond::Millisecond;

fn main() {
    let computed_millis = 33023448000;
    let ms = Millisecond::from_millis(computed_millis);
    println!("default: {ms}"); // 1y 17d 5h 10m 48s
    println!("  short: {}", ms.to_short_string()); // 1y 17d 5h 10m 48s
    println!("   long: {}", ms.to_long_string()); // 1 year 17 days 5 hours 10 minutes 48 seconds
}

Conclusion

Converting time into a human-readable format can be challenging in Rust. The millisecond crate provides a better way to overcome the situation. It is easy to use, has zero dependencies, is suitable for embedded environments, and is built up with the no_std attribute. The crate follows the MIT license and is inspired by pretty-ms the NPM package.

References

Repository: https://crates.io/crates/millisecond
The source code at Github: https://github.com/raeisimv/millisecond