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Dharmen Shah for Angular Material Dev

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Toggle dark theme in Angular Material

In one of our previous articles, we saw how to lazy load a dark theme. If you haven't already, please check it first:

Now, to load the "dark-theme.css" based on user's choice, we will create a simple service called "StyleManager":

// style-manager.service.ts

import { Injectable } from '@angular/core';

@Injectable({ providedIn: 'root' })
export class StyleManager {
  isDark = false;

  toggleDarkTheme() {
    if (this.isDark) {
      this.isDark = false;
    } else {
      const href = 'dark-theme.css';
      getLinkElementForKey('dark-theme').setAttribute('href', href);
      this.isDark = true;

  removeStyle(key: string) {
    const existingLinkElement = getExistingLinkElementByKey(key);
    if (existingLinkElement) {

function getLinkElementForKey(key: string) {
  return getExistingLinkElementByKey(key) || createLinkElementWithKey(key);

function getExistingLinkElementByKey(key: string) {
  return document.head.querySelector(

function createLinkElementWithKey(key: string) {
  const linkEl = document.createElement('link');
  linkEl.setAttribute('rel', 'stylesheet');
  return linkEl;

function getClassNameForKey(key: string) {
  return `style-manager-${key}`;
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Then you can inject the "StyleManager" service, and call "toggleDarkTheme" whenever you want!

// src/app/app.component.ts

import { Component } from '@angular/core';
import { StyleManager } from './services/style-manager.service';

  selector: 'app-root',
  templateUrl: './app.component.html'
export class AppComponent {
  title = 'my-app';
  isDark = this.styleManager.isDark;

  private styleManager = inject(StyleManager);

  toggleDarkTheme() {
    this.isDark = !this.isDark;
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That's it!!! For more information, read full article at:

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