Vuetify toggle between light and dark theme (with vuex)

Question

so in my Vue-project I basically have two pages/components that will be shown with the use of vue-router depending on the URL. I can switch between those pages/components via a button.

I am also using VueX for the management of some data.

Now I included a switch in one of the components to toggle between a dark and a light theme from Vuetify.

In the template for this component I do:

    <v-switch
      label="Toggle dark them"
      @change="toggleDarkTheme()"
    ></v-switch>

And in the function that gets called I do:

    toggleDarkTheme() {
          this.$vuetify.theme.dark = !this.$vuetify.theme.dark;
          console.log(this.$vuetify.theme.dark);
    },

In app.vue I have included the <v-app dark> and in my main.js i have the following:

    Vue.use(Vuetify);
    const vuetify = new Vuetify({
      theme: {
        // dark: true,
        themes: {
          light: {
            primary: colors.purple,
            secondary: colors.grey.darken1,
            accent: colors.shades.black,
            error: colors.red.accent3,
            background: colors.indigo.lighten5, 
          },
          dark: {
            primary: colors.blue.lighten3,
            background: colors.indigo.base,
          },
        },
      },
    });
    
    Vue.config.productionTip = false;
    
    new Vue({
      router,
      store,
      vuetify,
      render: (h) => h(App),
    }).$mount('#app');

So my problem now is, when I click the switch, the theme is indeed toggled from light to dark mode in this component. Light mode is the default and when I click the switch once, I get dark theme. However when I click the button to switch to the other URL, there the light theme will be used. How do I implement this feature correctly?

Thanks in advance!

Answer 1

You should have a JavaScript class called vuetify.js, that should look like this in your case.

import Vue from "vue";
import Vuetify from "vuetify/lib";

Vue.use(Vuetify);

export default new Vuetify({
  theme: {
    themes: {
      light: {
        primary: colors.purple,
        secondary: colors.grey.darken1,
        accent: colors.shades.black,
        error: colors.red.accent3,
        background: colors.indigo.lighten5
      },
      dark: {
        primary: colors.blue.lighten3,
        background: colors.indigo.base
      }
    }
  }
});

Your switch should be working, but just in case, try this button I've made in your component.

    <div>
      <v-tooltip v-if="!$vuetify.theme.dark" bottom>
        <template v-slot:activator="{ on }">
          <v-btn v-on="on" color="info" small fab @click="darkMode">
            <v-icon class="mr-1">mdi-moon-waxing-crescent</v-icon>
          </v-btn>
        </template>
        <span>Dark Mode On</span>
      </v-tooltip>

      <v-tooltip v-else bottom>
        <template v-slot:activator="{ on }">
          <v-btn v-on="on" color="info" small fab @click="darkMode">
            <v-icon color="yellow">mdi-white-balance-sunny</v-icon>
          </v-btn>
        </template>
        <span>Dark Mode Off</span>
      </v-tooltip>
    </div>

The Button calls this method in your <script>

darkMode() {
      this.$vuetify.theme.dark = !this.$vuetify.theme.dark;
    }

Answer 2

The below code creates a dark mode toggle switch btn.

Note: Its use Localstore

DarkModeToggel.vue

---

<template>
   <v-icon class="mr-2">
      mdi-brightness-4
   </v-icon>
   <v-list-item-title class="pr-10">
      Dark Mode
   </v-list-item-title>
   <v-switch v-model="darkmode" color="primary" />
</template>

--

<script>
export default {
  data () {
    return {
      darkmode: false
    }
  },
  watch: {
    darkmode (oldval, newval) {
      this.handledarkmode()
    }
  },
  created () {
    if (process.browser) {
      if (localStorage.getItem('DarkMode')) {
        const cookieValue = localStorage.getItem('DarkMode') === 'true'
        this.darkmode = cookieValue
      } else {
        this.handledarkmode()
      }
    }
  },
  methods: {
    handledarkmode () {
      if (process.browser) {
        if (this.darkmode === true) {
          this.$vuetify.theme.dark = true
          localStorage.setItem('DarkMode', true)
        } else if (this.darkmode === false) {
          this.$vuetify.theme.dark = false
          localStorage.setItem('DarkMode', false)
        }
      }
    }
  }
}
</script>

@ckuessner answer is working but not persistent.