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Without importing OnInit and implements
ngOnInit(){
this.recipies=this.recipeService.getRecipies();
}
This is still working fine without any complain so why should i use like :
import { Component,EventEmitter,Output , OnInit } from '@angular/core';
export class RecipiesListComponent implements OnInit{}
247
ngOnInit() is a place to put the code that we need to execute at very first as soon as the class is instantiated.
We import OnInit in order to use it, implementing OnInit is not mandatory but considered good practice): import {Component, OnInit} from '@angular/core'; We use ngOnInit to do something after the component has been created. for example you can set variables here, call methods etc.
A callback method that is invoked immediately after the default change detector has checked the directive's data-bound properties for the first time, and before any of the view or content children have been checked. It is invoked only once when the directive is instantiated.
The constructor() should only be used to initialize class members but shouldn't do actual “work”. So we should use constructor() to set up Dependency Injection, Initialization of class fields, etc. ngOnInit() is a better place to write “actual work code” that we need to execute as soon as the class is instantiated.
Interface are optional as per the angular documentation so you can use it without importing and implementing it.
Angular instead inspects directive and component classes and calls the hook methods if they are defined but it's good practice to add interfaces to TypeScript directive classes in order to benefit from strong typing and editor tooling.
66
We have to import OnInit in order to use like this (actually implementing OnInit is not mandatory but considered good practice).
import {Component, OnInit} from 'angular2/core';
Check this Link. Hope you got your answer.
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