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nodejs

typescript 
import { readFileSync } from 'fs';
import { join } from 'path';
import type { Redis } from 'ioredis';
import { randomUUID } from 'crypto';

export interface LimitResult {

Rate limiting by IP + user (Express)

security express redis
by codesnips 4 tabs
javascript 
const express = require('express');
const webhookRouter = require('./webhookRouter');
const apiRouter = require('./apiRouter');

const app = express();

Verify Stripe Webhook Signatures with a Raw-Body Express Route

express stripe webhooks
by codesnips 3 tabs
javascript 
function escapeCell(value) {
  if (value === null || value === undefined) return '';
  const str = String(value);
  if (/[",\n\r]/.test(str)) {
    return '"' + str.replace(/"/g, '""') + '"';
  }

Stream a Large CSV Export in Express with Backpressure and an Async Row Generator

express streaming csv
by codesnips 3 tabs
javascript 
const { z } = require('zod');

const ConfigSchema = z.object({
  env: z.enum(['development', 'test', 'production']).default('development'),
  port: z.coerce.number().int().positive().default(3000),
  database: z.object({

Cached Config Singleton in Node.js: Load Once, Share Everywhere

nodejs configuration singleton
by codesnips 3 tabs
javascript 
'use strict';

function dedupeAsync(producer, keyFn) {
  const pending = new Map();
  const resolveKey = keyFn || ((...args) => JSON.stringify(args));

Deduplicate Concurrent Async Calls With a Promise Cache in Node.js

nodejs async promises
by codesnips 3 tabs
javascript 
const express = require('express');
const AppError = require('./AppError');
const asyncHandler = require('./asyncHandler');
const errorMiddleware = require('./errorMiddleware');
const UserRepo = require('./UserRepo');

Centralized Express Error Handling with Typed AppError and Async Wrapper

express error-handling middleware
by codesnips 4 tabs
javascript 
'use strict';

const { Transform } = require('stream');

class LineSplitter extends Transform {
  constructor(options = {}) {

Split a Large Log File Into Date-Based Chunks With a Node.js Transform Stream

nodejs streams backpressure
by codesnips 3 tabs
javascript 
const MAX_LIMIT = 100;
const DEFAULT_LIMIT = 20;
const ALLOWED_ORDER = new Set(['asc', 'desc']);

function decodeCursor(raw) {
  const json = Buffer.from(raw, 'base64').toString('utf8');

Cursor-Based Pagination in Express With Query-Parsing Middleware

express pagination cursor-pagination
by codesnips 3 tabs
javascript 
const multer = require('multer');

const ALLOWED_MIME = new Set(['image/jpeg', 'image/png', 'image/webp']);

function fileFilter(req, file, cb) {
  if (!ALLOWED_MIME.has(file.mimetype)) {

Upload and Resize User Avatars with Multer and Sharp in Express

express multer sharp
by codesnips 3 tabs
javascript 
const withTimeout = (promise, timeoutMs, name) => {
  let timer;
  const timeout = new Promise((_, reject) => {
    timer = setTimeout(
      () => reject(new Error(`check '${name}' timed out after ${timeoutMs}ms`)),
      timeoutMs

Express Health-Check Router With a Pluggable Dependency Checks Registry

express health-check observability
by codesnips 3 tabs
javascript 
class ApiError extends Error {
  constructor(statusCode, message, code) {
    super(message);
    this.name = 'ApiError';
    this.statusCode = statusCode;
    this.code = code || null;

Centralized Async Error Handling in Express With asyncHandler and Error Middleware

express nodejs error-handling
by codesnips 4 tabs
javascript 
class BatchLoader {
  constructor(batchFn, { cacheKeyFn = (k) => k } = {}) {
    this.batchFn = batchFn;
    this.cacheKeyFn = cacheKeyFn;
    this.cache = new Map();
    this.queue = [];

Coalescing Concurrent Reads with a DataLoader-Style Batch Loader in Node

dataloader batching graphql
by codesnips 3 tabs