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
javascript
export const CACHE_VERSION = 'v7';

export const APP_SHELL = '/index.html';

export const PRECACHE_URLS = [
  '/',

Service worker: cache static assets safely

web performance pwa
by codesnips 3 tabs
typescript
import { onCLS, onINP, onLCP, onFCP, onTTFB, type Metric } from 'web-vitals';

export interface VitalPayload {
  id: string;
  name: Metric['name'];
  value: number;

Web Vitals reporting to an API endpoint

performance observability react
by codesnips 3 tabs
typescript
import { NextRequestWithAuth } from 'next/server';
import { NextResponse } from 'next/server';
import type { NextRequest } from 'next/server';
import { verifySession } from './lib/verify-session';
import { isProtected, isAuthPage } from './lib/route-matchers';

Next.js middleware for auth gating

nextjs auth security
by codesnips 3 tabs
typescript
import { z } from 'zod';

export const signupSchema = z
  .object({
    email: z.string().min(1, 'Email is required').email('Enter a valid email'),
    password: z

React Hook Form + Zod resolver

react forms react-hook-form
by codesnips 3 tabs
typescript
import { http, HttpResponse } from 'msw';

export interface Product {
  id: number;
  name: string;
}

MSW for frontend API mocking in tests

testing frontend react
by codesnips 4 tabs
typescript
import { readFileSync } from 'fs';
import { join } from 'path';
import Handlebars from 'handlebars';
import mjml2html from 'mjml';
import { htmlToText } from 'html-to-text';

Email sending with nodemailer + templates

node email nodemailer
by codesnips 3 tabs
typescript
type AsyncTask = () => Promise<void>;

export interface GuardOptions {
  name: string;
  logger?: Pick<Console, "info" | "warn" | "error">;
}

Cron scheduling with node-cron (with guard)

reliability node-cron cron
by codesnips 3 tabs
typescript
import { Queue } from "bullmq";
import { createHash } from "crypto";

export const connection = { host: "127.0.0.1", port: 6379 };

export interface ChargePayload {

BullMQ job idempotency via dedupe id

node redis background-jobs
by codesnips 3 tabs
sql
CREATE TABLE subscriptions (
    id                  BIGGENERATED ALWAYS AS IDENTITY PRIMARY KEY,
    customer_id         BIGINT       NOT NULL,
    plan_code           TEXT         NOT NULL,
    status              TEXT         NOT NULL DEFAULT 'active',
    current_period_end  TIMESTAMPTZ  NOT NULL,

Partial index for “active” rows in Postgres

postgres performance sql
by codesnips 3 tabs
typescript
import { Pool } from "pg";

async function keyFor(pool: Pool, name: string): Promise<string> {
  const { rows } = await pool.query<{ key: string }>(
    "SELECT hashtextextended($1, 0) AS key",
    [name]

Postgres advisory lock for one-at-a-time work

postgres concurrency reliability
by codesnips 3 tabs
sql
CREATE TABLE password_reset_tokens (
  id          BIGSERIAL PRIMARY KEY,
  user_id     BIGINT NOT NULL REFERENCES users(id) ON DELETE CASCADE,
  token_hash  TEXT NOT NULL,
  expires_at  TIMESTAMPTZ NOT NULL,
  used_at     TIMESTAMPTZ,

Password reset tokens: hash + expiry

security express authentication
by codesnips 3 tabs