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Working Angular 2 meta service with solution for "export function getDOM()" error
/**
* @license
* Copyright Google Inc. All Rights Reserved.
*
* Use of this source code is governed by an MIT-style license that can be
* found in the LICENSE file at https://angular.io/license
*/
import { Injectable, Inject } from '@angular/core';
import { DomAdapter } from '@angular/platform-browser/src/dom/dom_adapter';
import { __platform_browser_private__, DOCUMENT} from '@angular/platform-browser';
/**
* Represent meta element.
*
* ### Example
*
* ```ts
* { name: 'application-name', content: 'Name of my application' },
* { name: 'description', content: 'A description of the page', id: 'desc' }
* // ...
* // Twitter
* { name: 'twitter:title', content: 'Content Title' }
* // ...
* // Google+
* { itemprop: 'name', content: 'Content Title' },
* { itemprop: 'description', content: 'Content Title' }
* // ...
* // Facebook / Open Graph
* { property: 'fb:app_id', content: '123456789' },
* { property: 'og:title', content: 'Content Title' }
* ```
*
* @experimental
*/
export interface MetaDefinition {
charset?: string;
content?: string;
httpEquiv?: string;
id?: string;
itemprop?: string;
name?: string;
property?: string;
scheme?: string;
url?: string;
[prop: string]: string;
}
/**
* A service that can be used to get and add meta tags.
*
* @experimental
*/
@Injectable()
export class Meta {
private _dom: DomAdapter = __platform_browser_private__.getDOM();
constructor( @Inject(DOCUMENT) private _document: any) { }
/**
* Sets the title of the page
*/
setTitle(title: string) {
this._document.title = title
}
/**
* Adds a new meta tag to the dom.
*
* ### Example
*
* ```ts
* const name: MetaDefinition = {name: 'application-name', content: 'Name of my application'};
* const desc: MetaDefinition = {name: 'description', content: 'A description of the page'};
* const tags: HTMLMetaElement[] = this.meta.addTags([name, desc]);
* ```
*
* @param tags
* @returns {HTMLMetaElement[]}
*/
addTags(...tags: Array<MetaDefinition | MetaDefinition[]>): HTMLMetaElement[] {
if (isNode) { // Avoid readding the meta tags in client
const presentTags = this._flattenArray(tags);
if (presentTags.length === 0) return [];
return presentTags.map((tag: MetaDefinition) => this._addInternal(tag));
}
}
private _addInternal(tag: MetaDefinition): HTMLMetaElement {
const meta: HTMLMetaElement = this._createMetaElement();
this._prepareMetaElement(tag, meta);
this._appendMetaElement(meta);
return meta;
}
private _createMetaElement(): HTMLMetaElement {
return this._dom.createElement('meta') as HTMLMetaElement;
}
private _prepareMetaElement(tag: MetaDefinition, el: HTMLMetaElement): HTMLMetaElement {
Object.keys(tag).forEach((prop: string) => this._dom.setAttribute(el, prop, tag[prop]));
return el;
}
private _appendMetaElement(meta: HTMLMetaElement): void {
const head = this._document.head;
this._dom.appendChild(head, meta);
}
private _flattenArray(input: any[], out: any[] = []): any[] {
if (input) {
for (let i = 0; i < input.length; i++) {
const item: any = input[i];
if (Array.isArray(item)) {
this._flattenArray(item, out);
} else if (item) {
out.push(item);
}
}
}
return out;
}
}

Remember to IMport the isNode flag.

import { isNode } from 'angular2-universal';

Doesnt seem to actually render the tags on the server though? When i inspect my website i see them, but when i view source they are not there.

only client side rendering......

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