imkrish

//Make the following test cases pass

function isPalindrome(phrase) {
  const SPACE = " ";
  const lowerCharsInPhrase = phrase
    .toLowerCase()
    .split("")
    .filter(char => char !== SPACE);
  return lowerCharsInPhrase.join() === lowerCharsInPhrase.reverse().join();
}

imkrish

const maybePerson = getPerson();

console.log(maybePerson?.name);

console.log(maybePerson?.name?.firstName);

console.log(maybePerson?.name?.lastName);

console.log(maybePerson?.name?.getFullName?.());

imkrish

const maybePerson = getPerson();

if (maybePerson) {
	console.log(maybePerson.name);
}

if (maybePerson && maybePerson.name) {
	console.log(maybePerson.name.firstName);
	console.log(maybePerson.name.lastName);
}

imkrish

function getRandomNumber() {
	return Math.floor(Math.random() * 100);
}

function isEvenNumber(number: number) {
	return number % 2 == 0;
}

function getPerson() {
	if (isEvenNumber(getRandomNumber())) {

imkrish

export class AppComponent implements OnInit, OnDestroy {
  @Selector(CustomersState.SelectedCustomer)
  private selectedCustomer$: Observable<Customer>;

  @Selector(OrdersState.NewOrder)
  private newOrder$: Observable<Order>;

  private onComponentDestroy$: Subject<void>;

  constructor() {

imkrish

import { Component, OnDestroy, OnInit } from '@angular/core';
import { Observable, Subscription } from 'rxjs';

export class RxJSUtil {
  static unsubscribe = (subscriptions: Subscription[]) =>
    subscriptions.forEach(subscription => subscription.unsubscribe());
}

@Component({
  selector: 'nx-tutorial-root',

imkrish

type DeepReadonlyObject<T> = { readonly [K in keyof T]: DeepReadonly<T[K]> };

type DeepReadonly<T> = T extends (infer E)[][]
  ? ReadonlyArray<ReadonlyArray<DeepReadonlyObject<E>>>
  : T extends (infer E)[]
  ? ReadonlyArray<DeepReadonlyObject<E>>
  : T extends object
  ? DeepReadonlyObject<T>
  : T;

imkrish

interface User {
  readonly id: number;
  readonly name: string;
  readonly wifeName: string;
  readonly parents: ReadonlyArray<string>;
}

const user: User = {
  id: 1,
  name: "John",

imkrish

const numbers: ReadonlyArray<number> = [1, 2, 3, 4, 5];
numbers.push(6); // Property 'push' does not exist on type 'ReadonlyArray<number>'

imkrish

const numbers: number[] = [1, 2, 3, 4, 5];
numbers.push(6); // There is nothing wrong with this