Twitter widget on Angular 2

问题

I created a Twitter widget and I'm trying to put it in my Angular 2 project, but the JS file does not work.

If I insert it with JS (Here) it works, but when I switch to another tab and back (I have Angular Routing installed) it disappears and shows whatever is in A tag (so, "Tweets by ...").

HTML code (it's in home component):

<md-card-content>
  <a class="twitter-timeline" data-lang="en" data-height="350" data-theme="light" data-chrome="noborders nofooter noheader noscrollbar transparent" href="https://twitter.com/profile">Tweets by profile</a>
</md-card-content>

Script in home.component.ts, the code was provided by @Arg0n (look in answers section):

import { Component, OnInit } from '@angular/core';
import { Router, NavigationEnd } from '@angular/router';

@Component({
  selector: 'app-home',
  templateUrl: './home.component.html',
  styleUrls: ['./home.component.css']
})
export class HomeComponent implements OnInit {

  constructor(private _router : Router) { }

  public ngOnInit() {
    this._router.events.subscribe(val => {
      if (val instanceof NavigationEnd) {
        (<any>window).twttr = (function (d, s, id) {
            let js: any, fjs = d.getElementsByTagName(s)[0],
                t = (<any>window).twttr || {};
            if (d.getElementById(id)) return t;
            js = d.createElement(s);
            js.id = id;
            js.src = "https://platform.twitter.com/widgets.js";
            fjs.parentNode.insertBefore(js, fjs);

            t._e = [];
            t.ready = function (f: any) {
                t._e.push(f);
            };

            return t;
        }(document, "script", "twitter-wjs"));
        twttr.widgets.load();
      }
    })
  }

}

EDIT: Alright, I did some research and found out that I have to load the widget again with twttr.widgets.load(); but doing that, it throws me an error.

I edited the code above, so you can see what I've tried. The code above returns an error:

[ts] Cannot find name 'twttr'

if I append (window). to it, it throws me this:

EXCEPTION: Uncaught (in promise): TypeError: Cannot read property 'load' of undefined

The documentation on load property is here: https://dev.twitter.com/web/javascript/initialization

回答1:

Alright, I found a solution to this. When we switch between Angular routers, the widget unloads. That's why we put a subscriber, so we load the widget every time we switch between tabs. We can see here how to load the widget for lazy-loading content. When the page is ready, we can use that function to load the widget. Don't forget to unsubscribe after the view is destroyed!

Code:

import { Component, OnDestroy } from '@angular/core';
import { Router, NavigationEnd } from '@angular/router';

@Component({ ... })

export class HomeComponent implements OnDestroy {
  private twitter: any;

  constructor(private _router: Router) {
    this.initTwitterWidget();
  }

  initTwitterWidget() {
    this.twitter = this._router.events.subscribe(val => {
      if (val instanceof NavigationEnd) {
        (<any>window).twttr = (function (d, s, id) {
          let js: any, fjs = d.getElementsByTagName(s)[0],
              t = (<any>window).twttr || {};
          if (d.getElementById(id)) return t;
          js = d.createElement(s);
          js.id = id;
          js.src = "https://platform.twitter.com/widgets.js";
          fjs.parentNode.insertBefore(js, fjs);

          t._e = [];
          t.ready = function (f: any) {
              t._e.push(f);
          };

          return t;
        }(document, "script", "twitter-wjs"));

        if ((<any>window).twttr.ready())
          (<any>window).twttr.widgets.load();

      }
    });
  }

  ngOnDestroy() {
    this.twitter.unsubscribe();
  }
}

回答2:

Example for my comment (relevant parts):

import { Component, OnInit } from '@angular/core';
import { Router, NavigationEnd } from '@angular/router';

@Component({ ... })
export class MyComponent implements OnInit {
  constructor(private _router: Router) {}

  public ngOnInit() {
    this._router.events.subscribe(val => {
      if (val instanceof NavigationEnd) {
        (<any>window).twttr = (function (d, s, id) {
            let js: any, fjs = d.getElementsByTagName(s)[0],
                t = (<any>window).twttr || {};
            if (d.getElementById(id)) return t;
            js = d.createElement(s);
            js.id = id;
            js.src = "https://platform.twitter.com/widgets.js";
            fjs.parentNode.insertBefore(js, fjs);

            t._e = [];
            t.ready = function (f: any) {
                t._e.push(f);
            };

            return t;
        }(document, "script", "twitter-wjs"));
      }
    });
  }
}

回答3:

This will work for me on angular 7.2.2 and ionic 4.1. angular can build and ionic can build app and test on cordova.

solution from : embedded Twitter widget on Angular 2+ app only shows up on the first page load

import { Component, OnInit, OnDestroy, AfterViewInit, PLATFORM_ID, Inject } from '@angular/core';
import { isPlatformBrowser } from '@angular/common';

constructor(@Inject(PLATFORM_ID) private platformId: Object) {}

ngAfterViewInit() {
  if (isPlatformBrowser(this.platformId)) {
    setTimeout(function() {
      (<any>window).twttr = (function(d, s, id) {
        let js, fjs = d.getElementsByTagName(s)[0], t = (<any>window).twttr || {};

        if (d.getElementById(id)) return t;
        js = d.createElement(s);
        js.id = id;
        js.src = 'https://platform.twitter.com/widgets.js';
        fjs.parentNode.insertBefore(js, fjs);
        t._e = [];
        t.ready = function(f) {
          t._e.push(f);
        };
        return t;
      }(document, 'script', 'twitter-wjs'));
      (<any>window).twttr.widgets.load();
    }, 100);
  }
}

put here in .ts and put twitter tag in template files

来源：https://stackoverflow.com/questions/42993859/twitter-widget-on-angular-2