#rxjs code explainers

typescript

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

Wrapping requests in a transaction with NestJS

interceptors transactions rxjs

Advanced 7 steps

typescript

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';

A hover-triggered preloading strategy in Angular

lazy-loading rxjs preloading

Advanced 8 steps

typescript

import { Injectable } from '@angular/core';
import { HttpInterceptor, HttpRequest, HttpHandler, HttpEvent, HttpErrorResponse } from '@angular/common/http';
import { BehaviorSubject, Observable, throwError } from 'rxjs';
import { catchError, filter, take, switchMap } from 'rxjs/operators';

Refreshing auth tokens in an Angular interceptor

http-interceptor token-refresh rxjs

Advanced 8 steps

typescript

import {
  Injectable,
  NestInterceptor,
  ExecutionContext,

A per-route timeout interceptor in NestJS

interceptors metadata reflection rxjs

Intermediate 8 steps

typescript

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

A city autocomplete service in Angular

rxjs observables debouncing

Intermediate 7 steps

typescript

import { HttpService } from '@nestjs/axios';
import { Injectable, Logger, ServiceUnavailableException } from '@nestjs/common';
import { AxiosError } from 'axios';
import { catchError, firstValueFrom, retry, timer } from 'rxjs';

Resilient payment retries in NestJS

retry exponential-backoff rxjs

Advanced 8 steps

typescript

import { Component, OnInit, inject } from '@angular/core';
import { ActivatedRoute, Router } from '@angular/router';
import { FormBuilder } from '@angular/forms';
import { debounceTime, map } from 'rxjs/operators';

Syncing an Angular filter form with the URL

reactive-forms query-params rxjs

Intermediate 8 steps

typescript

import { inject } from '@angular/core';
import {
  ActivatedRouteSnapshot,
  CanActivateFn,

How a functional route guard works in Angular

route-guards dependency-injection rxjs

Intermediate 5 steps

typescript

import { Injectable } from '@angular/core';
import {
  HttpInterceptor,
  HttpHandler,

Refreshing tokens with an Angular HttpInterceptor

http-interceptor token-refresh rxjs

Advanced 8 steps

typescript

import { Injectable } from '@angular/core';
import { PreloadingStrategy, Route, Routes, RouterModule } from '@angular/router';
import { NgModule } from '@angular/core';
import { Observable, of, timer } from 'rxjs';

A custom preloading strategy in Angular

lazy-loading preloading rxjs

Intermediate 7 steps

typescript

import { Injectable } from '@angular/core';
import { HttpClient } from '@angular/common/http';
import {
  AsyncValidator,

How an async username validator works in Angular

async-validation reactive-forms rxjs

Intermediate 6 steps

typescript

import { inject } from '@angular/core';
import { ResolveFn, Router, ActivatedRouteSnapshot } from '@angular/router';
import { catchError, of, EMPTY } from 'rxjs';
import { Article } from './models/article';

Prefetching route data with an Angular resolver

route-resolver dependency-injection rxjs

Intermediate 6 steps

typescript

import {
  CallHandler,
  ExecutionContext,
  Injectable,

Wrapping responses in a NestJS interceptor

interceptors rxjs response-shaping

Intermediate 7 steps

typescript

import { Component } from '@angular/core';
import { FormControl, ReactiveFormsModule } from '@angular/forms';
import { HttpClient } from '@angular/common/http';
import { AsyncPipe } from '@angular/common';

Reactive type-ahead search in Angular

rxjs reactive-forms debounce

Intermediate 9 steps

typescript

import { HttpClient } from '@angular/common/http';
import { Injectable } from '@angular/core';
import { Observable, throwError, timer } from 'rxjs';
import { mergeMap, retryWhen } from 'rxjs/operators';

Exponential backoff retries in Angular

retry exponential-backoff rxjs

Advanced 7 steps

typescript

import {
  Injectable,
  NestInterceptor,
  ExecutionContext,

How a NestJS logging interceptor works

interceptors rxjs logging

Intermediate 5 steps