Unlocking the power of global JavaScript variables within an Angular 2 component

Question

Unlocking the power of global JavaScript variables within an Angular 2 component

Below, you will find a global JavaScript variable that is defined. Note that @Url is an ASP.Net MVC html helper and it will be converted to a string value:

<script>
  var rootVar = '@Url.Action("Index","Home",new { Area = ""}, null)';
  System.import('app').catch(function(err){ console.error(err); });
</script>

I am wondering how I can access the rootVar in an Angular 2 component. In Angular 1.5, I used the window service for this purpose. Is there a similar way of achieving this in Angular 2?

Specifically, I aim to use the rootVar variable to assist in generating the templateUrl in the following component:

import { Component, Inject} from '@angular/core';

@Component({
    selector: 'home-comp',
    templateUrl: '../Home/Root'
})

export class HomeComponent {   
    constructor( ) {  }
}

typescript angular

Answer 1

Answer №1

If you need to access global variables within your component, you can do so by referencing the window object in the following ways:

rootVar = window["rootVar"];

or

let rootVar = window["rootVar"];

Answer 2

If you need to access global variables within your component, you can do so by referencing the window object in the following ways:

rootVar = window["rootVar"];

or

let rootVar = window["rootVar"];

Answer 3

Answer №2

To ensure the proper functioning of your application, it is essential to make some updates to the file responsible for bootstrapping:

import {bootstrap} from '...';
import {provide} from '...';
import {AppComponent} from '...';

export function main(rootVar) {
  bootstrap(AppComponent, [
    provide('rootVar', { useValue: rootVar })
  ]);
}

Once this update is made, you can pass the variable from the index.html file in the following manner:

<script>
  var rootVar = '@Url.Action("Index","Home",new { Area = ""}, null)';
  System.import('app/main').then((module) => {
    module.main(rootVar);
  });
</script>

Subsequently, you can inject the rootVar into components and services using this approach:

import { Component, Inject} from '@angular/core';

@Component({
  selector: 'home-comp',
  templateUrl: '../Home/Root'
})
export class HomeComponent {   
  constructor(@Inject('rootVar') rootVar:string ) {  }
}

Answer 4

To ensure the proper functioning of your application, it is essential to make some updates to the file responsible for bootstrapping:

import {bootstrap} from '...';
import {provide} from '...';
import {AppComponent} from '...';

export function main(rootVar) {
  bootstrap(AppComponent, [
    provide('rootVar', { useValue: rootVar })
  ]);
}

Once this update is made, you can pass the variable from the index.html file in the following manner:

<script>
  var rootVar = '@Url.Action("Index","Home",new { Area = ""}, null)';
  System.import('app/main').then((module) => {
    module.main(rootVar);
  });
</script>

Subsequently, you can inject the rootVar into components and services using this approach:

import { Component, Inject} from '@angular/core';

@Component({
  selector: 'home-comp',
  templateUrl: '../Home/Root'
})
export class HomeComponent {   
  constructor(@Inject('rootVar') rootVar:string ) {  }
}

Answer 5

Answer №3

To make a variable accessible in the component constructor, declare it outside of the component class definition within the component file:

declare var customVar: any;

Then, use it like this:

@Component(...)
export class NewComponent {
  private data: any;

  constructor() {
    this.data = customVar;
  }
}

Answer 6

To make a variable accessible in the component constructor, declare it outside of the component class definition within the component file:

declare var customVar: any;

Then, use it like this:

@Component(...)
export class NewComponent {
  private data: any;

  constructor() {
    this.data = customVar;
  }
}

Answer 7

Answer №4

Remember to always wash your hands... Angular is essentially JavaScript

//Access something from the global scope
let someStuffFromWindow= (<any>window).somethingOnWindow;

//Assign a new value
(<any>window).somethingOnWindow="Content From Angular";

This is not ideal and should be avoided! Reflect on your actions!

Feel free to utilize the find and replace function to convert window. to (<any>window).

Answer 8

Remember to always wash your hands... Angular is essentially JavaScript

//Access something from the global scope
let someStuffFromWindow= (<any>window).somethingOnWindow;

//Assign a new value
(<any>window).somethingOnWindow="Content From Angular";

This is not ideal and should be avoided! Reflect on your actions!

Feel free to utilize the find and replace function to convert window. to (<any>window).

Answer 9

Answer №5

One alternative strategy is to save your variable as a global constant, like this:

  const API_ENDPOINT = '@Url.Action("Index","Home",new { Area = ""}, null)';

Afterwards, you can simply import and use it in your component:

import {API_ENDPOINT }

Answer 10

One alternative strategy is to save your variable as a global constant, like this:

  const API_ENDPOINT = '@Url.Action("Index","Home",new { Area = ""}, null)';

Afterwards, you can simply import and use it in your component:

import {API_ENDPOINT }

Answer 11

Answer №6

Utilize the get method in an HTML template:

<span>{{getGlobalData('mainVar')}}</span>

To implement this functionality, define a method within a component:

get getGlobalData() {
    // Utilize a closure workaround
    return function(mainVarName) {
        return window[mainVarName];
    }
}

Answer 12

Utilize the get method in an HTML template:

<span>{{getGlobalData('mainVar')}}</span>

To implement this functionality, define a method within a component:

get getGlobalData() {
    // Utilize a closure workaround
    return function(mainVarName) {
        return window[mainVarName];
    }
}

Unlocking the power of global JavaScript variables within an Angular 2 component

Answer №1

Answer №2

Answer №3

Answer №4

Answer №5

Answer №6

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