How do I call a function/execute code automaticall

问题:

I have code in a function that I need for initialization of other variables. However, this function doesn't get called unless i call it through another tag in html. Is there any way that i can initialize this function or write the code in a way in which the code gets executed automatically as soon as the project starts executing the the website loads?

回答1:

You should have a look at lifecycle hooks that are used in Angular, here is the link to the documents related.

lifecycle hooks

In here you can read about the OnInit() lifecycle hook which is triggered when a component is loaded ( after constructor ) and is an ideal place to look at initialising variables / calling functions etc.

public ngOnInit(): void 
{
   //execute logic
   this.exampleText = 'Hello Component';
}

just make sure to implement it on your class like so

export class youClassHere implements OnInit {

    public exampleText: string;

    public ngOnInit(): void 
    {
       //executing logic on component load
       this.exampleText = 'Hello Component';
    }
}

回答2:

You can implement OnInit event and do it there. Take a look here OnInit. Check here if you want to now more about Lifecycle Hooks. Alternative option is to use constructor. But that's executed on class initialization.

class MyComponent implements OnInit {
  ngOnInit() {
    // ...
  }
}