Advanced code explainers

use axum::{extract::{Path, State}, http::StatusCode, Json};
use dashmap::DashMap;
use serde::Serialize;
use std::sync::Arc;

function attachThousandSeparators(input, { locale = 'en-US' } = {}) {
  const formatter = new Intl.NumberFormat(locale);
  const groupSep = formatter.format(11111).replace(/\d/g, '')[0] || ',';
  const decimalSep = formatter.format(1.1).replace(/\d/g, '')[0] || '.';

<?php
 
namespace App\Providers;
 

import { Injectable, NestInterceptor, ExecutionContext, CallHandler } from '@nestjs/common';
import { Observable, catchError, concatMap, finalize } from 'rxjs';
import { DataSource, QueryRunner } from 'typeorm';
 

const express = require('express');
const app = express();
 
app.get('/health', (req, res) => res.json({ status: 'ok' }));

func UploadChunk(c *gin.Context) {
	uploadID := c.Param("uploadID")
	if !validUploadID.MatchString(uploadID) {
		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid upload id"})

use axum::{
    body::Body,
    extract::Path,
    http::{header, HeaderMap, HeaderValue, StatusCode},

@GetMapping("/files/{id}")
public ResponseEntity<StreamingResponseBody> download(
        @PathVariable String id,
        @RequestHeader(value = HttpHeaders.RANGE, required = false) String rangeHeader) throws IOException {

import asyncio
import json
 
from fastapi import APIRouter, Depends, HTTPException

import { Injectable, inject } from '@angular/core';
import { PreloadingStrategy, Route } from '@angular/router';
import { Observable, of, Subject } from 'rxjs';
import { filter, switchMap, take } from 'rxjs/operators';

from decimal import Decimal, ROUND_HALF_UP
 
from django.db import transaction
from django.db.models import F

const express = require('express');
const { AsyncLocalStorage } = require('async_hooks');
const { randomUUID } = require('crypto');
 

package middleware
 
import (
	"bytes"

class Pipeline
  def initialize
    @middlewares = []
  end

package middleware
 
import (
	"context"

public final class MultipartParser {
 
    public record FilePart(String name, String filename, String contentType, byte[] content) {}
 

use axum::{
    body::Body,
    extract::State,
    http::{header, StatusCode},

final class Container
{
    private array $bindings = [];
    private array $instances = [];