Angular is throwing an error that Localstorage is not defined

Question

Angular is throwing an error that Localstorage is not defined

I'm currently working on a project and have encountered an issue with utilizing localStorage. My goal is to save the count state when the add button is clicked, so that even if I refresh the page, the number will remain intact.

--- cart.service.ts---
key= "count"

private Count = new BehaviorSubject<number>(this.getlocal());
Count$ = this.Count.asObservable();

incrementCount(){
   const newCont = this.Count.value+1;
   this.Count.next(newCont);
   this.setlocal(newCont);
 }

getlocal(): number {
  const storedValue = localStorage.getItem(this.key); 
  return storedValue !== null ? parseInt(storedValue, 10) : 0;
}

setlocal(count: number) {
  localStorage.setItem(this.key, count.toString());
}

Additionally, I have created an app component with the incrementcount function, along with a navcomponent that receives the count via HTML. However, I am encountering error ng0100. Any assistance in resolving this would be greatly appreciated!

angular typescript angular-ssr

Answer 1

Answer №1

When utilizing server-side rendering (SSR) and needing to access browser APIs, it is essential to enclose the code within an afterRender or afterNextRender block. Failure to do so may result in the code being executed on the server side (Node.JS), where functionalities like localStorage are not available. It is also crucial to adjust logic when fetching a value directly from local storage within a function.

private initialCount = new BehaviorSubject<number>(0);

constructor(private readonly environmentInjector: EnvironmentInjector) {
  afterNextRender(() => {
    const storedValue = localStorage.getItem(this.key);
    const count = storedValue !== null ? parseInt(storedValue, 10) : 0;
    this.initialCount.next(count);
  });
}

setLocalStorageCount(count: number) {
  runInInjectionContext(this.environmentInjector, () =>
    afterNextRender(() => localStorage.setItem(this.key, count.toString()))
  );
}

Answer 2

When utilizing server-side rendering (SSR) and needing to access browser APIs, it is essential to enclose the code within an afterRender or afterNextRender block. Failure to do so may result in the code being executed on the server side (Node.JS), where functionalities like localStorage are not available. It is also crucial to adjust logic when fetching a value directly from local storage within a function.

private initialCount = new BehaviorSubject<number>(0);

constructor(private readonly environmentInjector: EnvironmentInjector) {
  afterNextRender(() => {
    const storedValue = localStorage.getItem(this.key);
    const count = storedValue !== null ? parseInt(storedValue, 10) : 0;
    this.initialCount.next(count);
  });
}

setLocalStorageCount(count: number) {
  runInInjectionContext(this.environmentInjector, () =>
    afterNextRender(() => localStorage.setItem(this.key, count.toString()))
  );
}

Answer 3

Answer №2

To update the code in cart.service.ts, you can follow these instructions:

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

@Injectable({
  providedIn: 'root'
})
export class CartService {
  private readonly cartKey = 'cartCount';

  // Set initial count to 0 for each new session
  private cartCount = new BehaviorSubject<number>(0);
  cartCount$ = this.cartCount.asObservable();

  constructor() {
    // Reset localStorage count to 0 upon service initialization
    this.setLocalStorage(0);
  }

  incrementCartCount() {
    const newCartCount = this.cartCount.value + 1;
    this.cartCount.next(newCartCount);
    this.setLocalStorage(newCartCount);
  }


  private setLocalStorage(count: number) {
    if (typeof localStorage !== 'undefined') {
      localStorage.setItem(this.cartKey, count.toString());
    }
  }
}

Answer 4

To update the code in cart.service.ts, you can follow these instructions:

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

@Injectable({
  providedIn: 'root'
})
export class CartService {
  private readonly cartKey = 'cartCount';

  // Set initial count to 0 for each new session
  private cartCount = new BehaviorSubject<number>(0);
  cartCount$ = this.cartCount.asObservable();

  constructor() {
    // Reset localStorage count to 0 upon service initialization
    this.setLocalStorage(0);
  }

  incrementCartCount() {
    const newCartCount = this.cartCount.value + 1;
    this.cartCount.next(newCartCount);
    this.setLocalStorage(newCartCount);
  }


  private setLocalStorage(count: number) {
    if (typeof localStorage !== 'undefined') {
      localStorage.setItem(this.cartKey, count.toString());
    }
  }
}

Angular is throwing an error that Localstorage is not defined

Answer №1

Answer №2

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