field and value extraction using serde json

struct_extraction.rs

use serde::{Deserialize, Serialize};
use serde_json::Value;

  pub fn extraction<T: Default + Serialize>(data: &T) -> Value {
    let columns = serde_json::to_value(data.clone())
      .unwrap()
      .as_object()
      .unwrap()
      .keys()
      .map(|key| key.to_string())
      .collect::<Vec<String>>();

    match serde_json::to_value(data) {
      Ok(Value::Object(mut map)) => {
        map.retain(|k, v| columns.contains(&k.to_string()) && !v.is_null());
        Value::Object(map)
      },
      _ => Value::Null,
    }
  }

Add preserve_order and indexmap feature flag to serde_json

serde_json = { version = "1.0.107", features = ["preserve_order", "indexmap"] }
serde = { version = "1.0.188", features = ["derive"] }