nushell/src/commands/sort_by.rs

use crate::errors::ShellError;
use crate::prelude::*;

pub fn sort_by(args: CommandArgs, registry: &CommandRegistry) -> Result<OutputStream, ShellError> {
    let args = args.evaluate_once(registry)?;
    let (input, args) = args.parts();

    let fields: Result<Vec<_>, _> = args
        .positional
        .iter()
        .flatten()
        .map(|a| a.as_string())
        .collect();

    let fields = fields?;

    let output = input.values.collect::<Vec<_>>();

    let output = output.map(move |mut vec| {
        vec.sort_by_key(|item| {
            fields
                .iter()
                .map(|f| item.get_data_by_key(f).map(|i| i.clone()))
                .collect::<Vec<Option<Spanned<Value>>>>()
        });

        vec.into_iter().collect::<VecDeque<_>>()
    });

    Ok(output.flatten_stream().from_input_stream())
}