#singleton code explainers

go

package config
 
import (
	"fmt"

A thread-safe config singleton in Go

singleton concurrency environment-variables

Intermediate 7 steps

typescript

import { DynamicModule, Module, Provider } from '@nestjs/common';
import Redis, { RedisOptions } from 'ioredis';
 
export const REDIS_CLIENT = Symbol('REDIS_CLIENT');

Building a dynamic Redis module in NestJS

dependency-injection dynamic-modules provider-tokens

Intermediate 8 steps

typescript

import { Injectable } from '@angular/core';
import { HttpClient } from '@angular/common/http';
import { Observable, shareReplay } from 'rxjs';

Caching HTTP config in an Angular service

caching observables dependency-injection

Intermediate 6 steps

typescript

// A module-scoped Singleton: the single instance lives in this module's
// closure and is never exposed directly.
 
interface AppConfig {

A module-scoped Singleton in TypeScript

singleton generics encapsulation

Intermediate 7 steps