typescript
import crypto from 'crypto';
import helmet from 'helmet';
import type { Express, Request, Response, NextFunction } from 'express';

function cspNonce(req: Request, res: Response, next: NextFunction): void {
  res.locals.cspNonce = crypto.randomBytes(16).toString('base64');

Security headers with helmet (baseline hardening)

security express helmet
by codesnips 3 tabs
typescript
import { Readable } from "node:stream";
import { S3Client } from "@aws-sdk/client-s3";
import { Upload } from "@aws-sdk/lib-storage";

const s3 = new S3Client({ region: process.env.AWS_REGION });
const BUCKET = process.env.UPLOAD_BUCKET!;

Multipart upload streaming (busboy)

busboy express s3
by codesnips 3 tabs
sql
CREATE TABLE daily_metrics (
    id          BIGGENERATED ALWAYS AS IDENTITY PRIMARY KEY,
    tenant_id   BIGINT      NOT NULL,
    metric      TEXT        NOT NULL,
    day         DATE        NOT NULL,
    count       BIGINT      NOT NULL DEFAULT 0,

SQL upsert for counters (ON CONFLICT DO UPDATE)

postgres sql concurrency
by codesnips 3 tabs
typescript
import { useCallback, useEffect, useRef, useState } from 'react';

export type CopyStatus = 'idle' | 'copied' | 'error';

function fallbackCopy(text: string): boolean {
  const textarea = document.createElement('textarea');

Frontend: copy-to-clipboard with fallback

frontend ux react
by codesnips 3 tabs
typescript
export class AppError extends Error {
  public readonly statusCode: number;
  public readonly code: string;
  public readonly isOperational: boolean;

  constructor(message: string, statusCode = 500, code = 'INTERNAL_ERROR', isOperational = true) {

Backend: normalize errors with a single Express handler

express error-handling typescript
by codesnips 4 tabs
typescript
import React from 'react';
import { useToasts } from './useToasts';

export function Toaster() {
  const { toasts, dismiss } = useToasts();

Frontend: toast notifications via a small event bus

react frontend typescript
by codesnips 3 tabs
typescript
import { useEffect, useRef, useState } from "react";

export type AsyncState<T> =
  | { status: "loading" }
  | { status: "error"; error: Error }
  | { status: "success"; data: T };

Frontend: skeleton loading instead of spinners

react ux typescript
by codesnips 4 tabs
sql
CREATE TABLE events (
    id          bigint GENERATED ALWAYS AS IDENTITY PRIMARY KEY,
    source      text        NOT NULL,
    external_id text        NOT NULL,
    payload     jsonb       NOT NULL,
    occurred_at timestamptz NOT NULL,

Batched writes with COPY (conceptual)

postgres performance sql
by codesnips 3 tabs
typescript
import { PrismaClient } from '@prisma/client';

const prisma = new PrismaClient();

export async function getFeedNaive(limit = 20) {
  const posts = await prisma.post.findMany({

Prisma: avoid N+1 with include/select

prisma performance typescript
by codesnips 3 tabs
sql
-- Step 1: add the column nullable, no default.
-- Catalog-only change in Postgres 11+, returns instantly.
ALTER TABLE orders
  ADD COLUMN currency text;

-- Optional: keep the lock attempt bounded so a long-running

SQL migration safety: add column nullable, backfill, then constrain

postgres migrations reliability
by codesnips 3 tabs
typescript
import { createHash } from "crypto";
import { readFileSync } from "fs";

export function sha256(query: string): string {
  return createHash("sha256").update(query, "utf8").digest("hex");
}

GraphQL persisted queries (hash allowlist)

graphql security performance
by codesnips 3 tabs
typescript
import { initTRPC, TRPCError } from '@trpc/server';

export interface Context {
  user: { id: string; role: 'user' | 'admin' } | null;
  db: DatabaseClient;
}

tRPC router pattern for type-safe APIs

typescript trpc api
by codesnips 4 tabs