jlu 0.1.0

Command-line utilities for on-the-fly investigation of JSON Lines
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54

use crate::jsonl;
use orfail::OrFail;
use serde_json::{Map, Value};

/// Read JSON values from stdin and convert each value into a flattened JSON object.
#[derive(Debug, clap::Args)]
pub struct FlattenCommand {}

impl FlattenCommand {
    pub fn run(&self) -> orfail::Result<()> {
        let output_values = jsonl::from_stdin().map(|input_value| {
            let input_value = input_value.or_fail()?;
            let mut flattened = Map::new();
            flatten(input_value, "", &mut flattened);
            Ok(Value::Object(flattened))
        });
        jsonl::to_stdout(output_values).or_fail()?;
        Ok(())
    }
}

fn flatten(value: Value, prefix: &str, output: &mut Map<String, Value>) {
    match value {
        Value::Null => {
            output.insert(prefix.to_owned(), Value::Null);
        }
        Value::Bool(v) => {
            output.insert(prefix.to_owned(), Value::Bool(v));
        }
        Value::Number(v) => {
            output.insert(prefix.to_owned(), Value::Number(v));
        }
        Value::String(v) => {
            output.insert(prefix.to_owned(), Value::String(v));
        }
        Value::Array(array) => {
            let width = array.len().saturating_sub(1).to_string().len();
            for (i, v) in array.into_iter().enumerate() {
                let key = format!("{prefix}[{i:0width$}]");
                flatten(v, &key, output);
            }
        }
        Value::Object(object) => {
            for (k, v) in object {
                let key = if prefix.is_empty() {
                    k.clone()
                } else {
                    format!("{prefix}.{k}")
                };
                flatten(v, &key, output);
            }
        }
    }
}