yannickglt

// Avoid useless computations and combine the property and its initialization method
// Live demo at stackblitz.com/edit/angular-lazy-getter
import { Component, ChangeDetectionStrategy } from '@angular/core';
import { LazyGetter } from 'lazy-get-decorator';

@Component({
  selector: 'lazy-getter-usage',
  template: `
    <h1>{{ sayHelloWithLazyGetter }}</h1>
    <h1>{{ sayHelloWithoutLazyGetter() }}</h1>

yannickglt

// A safe way to call methods in templates
// Live demo @ https://stackblitz.com/edit/angular-generic-map-pipe
import { Pipe, PipeTransform } from "@angular/core";

// Methods passed to the map pipe cannot (and should not) use the `this` keyword from components. Otherwise, it would not be a pure pipe.
@Pipe({ name: "map" })
export class MapPipe implements PipeTransform {
  public transform<T, R>(
    thisArg: T,
    project: (t: T, ...others: any[]) => R,

yannickglt

// With "+" operator 

1 + undefined
// NaN

undefined + undefined
// NaN

"1" + "2"
// "12"