Is it possible to set a unique identifier in Vue.js that persists even after the page is reloaded?

Question

Is it possible to set a unique identifier in Vue.js that persists even after the page is reloaded?

Currently, I'm working on a small project diving into Vue js - a Habittracker. Unfortunately, there is a bug in my code. When the page is reloaded and new habits are added, the function that should change the background doesn't work as expected.

This link shows the bug. Here's a glimpse of how my array is structured:

0
: 
{id: 0, title: "1", ready: false}

1
: 
{id: 1, title: "123", ready: false}

2
: 
{id: 2, title: "123", ready: false}

3
: 
{id: 0, title: "123", ready: true}

The reason behind this issue lies in using a counter to assign the id, which resets to 0 upon reloading.

<div class="q-pa-md" v-for="(habit, index) in habits" :key="habit.id">
    <q-card class="my-card" :id="habit.id" ref="card">
      <q-card-section>
        <q-checkbox
          id="checkbox"
          v-model="habit.ready"
          @click="changeToTransparent(habit)"
        >
        </q-checkbox>
        {{ habit.title }}

        <q-btn-dropdown flat class="more" icon="more_horiz">
          <q-list>
            <q-item clickable v-close-popup @click="deletehabit(index)">
              <q-item-section>
                <q-item-label>Delete</q-item-label>
              </q-item-section>
            </q-item>

            <q-item clickable v-close-popup @click="edithabitbutton(index)">
              <q-item-section>
                <q-item-label>Edit</q-item-label>
              </q-item-section>
            </q-item>
          </q-list>
        </q-btn-dropdown>
      </q-card-section>
    </q-card>
    <div>

let counter = 0;
const habits = ref([]);


const addHabit = () => {
  
  habits.value.push({ id: counter++, title: habittitle.value, ready: false });
  savetolocalstorage();
  habittitle.value = "";
};

const changeToTransparent = (habit) => {

  if(document.getElementById(habit.id) != null) {
    if (habit.ready) {
    document.getElementById(habit.id).style.backgroundColor =
      "rgba(170,193,200,0.25)";
    savetolocalstorage();
  } else {
    document.getElementById(habit.id).style.backgroundColor = "";
    savetolocalstorage();
  }
  }
 
}

Do you have any suggestions or tips on how to tackle this problem?

javascript css vue.js local-storage quasar-framework

Answer 1

Answer №1

To utilize your localStorage effectively, ensure to initialize its length with the counter value. I have provided a functional demo for reference. Moreover, I have optimized your code to align better with Vue's principles. As advised by @Rahul Purohit, remember to use JSON.stringify when saving and JSON.parse when loading.

<template>
  <q-input label="Title" v-model="habitTitle" />
  <q-btn label="Add habit" @click="addHabit" />
  <div class="q-pa-md" v-for="(habit, index) in habits" :key="habit.id">
    <q-card
      class="my-card"
      :id="habit.id"
      :ref="(el) => (cardRefs[habit.id] = el)"
    >
      <q-card-section>
        <q-checkbox
          id="checkbox"
          v-model="habit.ready"
          @click="changeToTransparent(habit)"
        >
        </q-checkbox>
        {{ habit.id }} {{ habit.title }}

        <q-btn-dropdown flat class="more" icon="more_horiz">
          <q-list>
            <q-item clickable v-close-popup @click="deletehabit(index)">
              <q-item-section>
                <q-item-label>Delete</q-item-label>
              </q-item-section>
            </q-item>

            <q-item clickable v-close-popup @click="edithabitbutton(index)">
              <q-item-section>
                <q-item-label>Edit</q-item-label>
              </q-item-section>
            </q-item>
          </q-list>
        </q-btn-dropdown>
      </q-card-section>
    </q-card>
  </div>
</template>

<script setup>
const { ref, onMounted } = require("vue");

// it can be just a let.
const counter = ref(0);
const habits = ref([]);
const habitTitle = ref("test");
const cardRefs = ref({});

const saveToLocalStorage = () => console.log("saved");

const addHabit = () => {
  habits.value.push({
    id: counter.value++,
    title: habitTitle.value,
    ready: false,
  });
  saveToLocalStorage();
  habitTitle.value = "";
};

const changeToTransparent = (habit) => {
  if (cardRefs.value[habit.id] != null) {
    if (habit.ready) {
      cardRefs.value[habit.id].$el.style.backgroundColor =
        "rgba(170,193,200,0.25)";
      saveToLocalStorage();
    } else {
      cardRefs.value[habit.id].$el.style.backgroundColor = "";
      saveToLocalStorage();
    }
  }
};

onMounted(() => {
  // Load habits from localStorage
  // This is just an example
  habits.value = [
    {
      id: 0,
      title: "Testing new habit",
      ready: true,
    },
    {
      id: 1,
      title: "Testing new habit",
      ready: false,
    },
    {
      id: 2,
      title: "Testing new habit",
      ready: false,
    },
  ];
  counter.value = habits.value.length;
});
</script>

Answer 2

To utilize your localStorage effectively, ensure to initialize its length with the counter value. I have provided a functional demo for reference. Moreover, I have optimized your code to align better with Vue's principles. As advised by @Rahul Purohit, remember to use JSON.stringify when saving and JSON.parse when loading.

<template>
  <q-input label="Title" v-model="habitTitle" />
  <q-btn label="Add habit" @click="addHabit" />
  <div class="q-pa-md" v-for="(habit, index) in habits" :key="habit.id">
    <q-card
      class="my-card"
      :id="habit.id"
      :ref="(el) => (cardRefs[habit.id] = el)"
    >
      <q-card-section>
        <q-checkbox
          id="checkbox"
          v-model="habit.ready"
          @click="changeToTransparent(habit)"
        >
        </q-checkbox>
        {{ habit.id }} {{ habit.title }}

        <q-btn-dropdown flat class="more" icon="more_horiz">
          <q-list>
            <q-item clickable v-close-popup @click="deletehabit(index)">
              <q-item-section>
                <q-item-label>Delete</q-item-label>
              </q-item-section>
            </q-item>

            <q-item clickable v-close-popup @click="edithabitbutton(index)">
              <q-item-section>
                <q-item-label>Edit</q-item-label>
              </q-item-section>
            </q-item>
          </q-list>
        </q-btn-dropdown>
      </q-card-section>
    </q-card>
  </div>
</template>

<script setup>
const { ref, onMounted } = require("vue");

// it can be just a let.
const counter = ref(0);
const habits = ref([]);
const habitTitle = ref("test");
const cardRefs = ref({});

const saveToLocalStorage = () => console.log("saved");

const addHabit = () => {
  habits.value.push({
    id: counter.value++,
    title: habitTitle.value,
    ready: false,
  });
  saveToLocalStorage();
  habitTitle.value = "";
};

const changeToTransparent = (habit) => {
  if (cardRefs.value[habit.id] != null) {
    if (habit.ready) {
      cardRefs.value[habit.id].$el.style.backgroundColor =
        "rgba(170,193,200,0.25)";
      saveToLocalStorage();
    } else {
      cardRefs.value[habit.id].$el.style.backgroundColor = "";
      saveToLocalStorage();
    }
  }
};

onMounted(() => {
  // Load habits from localStorage
  // This is just an example
  habits.value = [
    {
      id: 0,
      title: "Testing new habit",
      ready: true,
    },
    {
      id: 1,
      title: "Testing new habit",
      ready: false,
    },
    {
      id: 2,
      title: "Testing new habit",
      ready: false,
    },
  ];
  counter.value = habits.value.length;
});
</script>

Answer 3

Answer №2

Based on the information provided, it seems like you are not utilizing a backend system and instead storing all data locally.

In this scenario, it appears that you are saving your entries in an array within local storage, possibly labeled as habits: []

Rather than setting the counter to 0 initially, consider incorporating a lifecycle method for more efficiency.

beforeMount() {
  counter = JSON.parse(localStorage.getItem("habits")).length
}

Answer 4

Based on the information provided, it seems like you are not utilizing a backend system and instead storing all data locally.

In this scenario, it appears that you are saving your entries in an array within local storage, possibly labeled as habits: []

Rather than setting the counter to 0 initially, consider incorporating a lifecycle method for more efficiency.

beforeMount() {
  counter = JSON.parse(localStorage.getItem("habits")).length
}

Is it possible to set a unique identifier in Vue.js that persists even after the page is reloaded?

Answer №1

Answer №2

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