When using @pinia/nuxt, placing the HTTP request outside setInterval will be executed on every setInterval iteration.

Question

I'm trying to build a timer using @pinia/nuxt and nuxt 3. When the timer starts, I also want to initiate an HTTP request to synchronize my database.

The problem I'm facing is that every time I call the start action, an HTTP request is made for each iteration of the setInterval loop, and I only want to run it once.

This is the pinia module. I call the start action in the component's onClick event.

state: () => ({
  timer: {
    id: null,
    isRunning: false,
    time: 5,
    timer: 0,
    state: null,
  } as Timer,
}),
actions: {
  start() {
    this.timer.isRunning = true
    this.syncTimer()
    if (!this.timer.timer) {
      this.timer.timer = setInterval(() => {
        if (this.timer.time > 0) {
          this.timer.time--
        } else {
          clearInterval(this.timer.timer)
          this.reset()
        }
      }, 1000)
    }
  },
  stop() {
    this.timer.isRunning = false
    clearInterval(this.timer.timer)
    this.timer.timer = 0
  },
  reset() {
    this.stop()
    this.timer.time = 1500
  },
  syncTimer() {
    backendAPI<Timer>('/api/timer', {
      method: 'POST',
      body: this.timer
    }).then(({ error, data }) => {
      if (!error.value) {
        const id = data.value?.id ?? ""
        this.timer.id = id
        this.timer.state = "created"
      }
    })
  }
}

My packages.json file is as follows:

"devDependencies": {
    "@fortawesome/fontawesome-free": "^6.4.0",
    "@fullcalendar/core": "^6.1.8",
    "@fullcalendar/daygrid": "^6.1.8",
    "@fullcalendar/interaction": "^6.1.8",
    "@fullcalendar/timegrid": "^6.1.8",
    "@fullcalendar/vue3": "^6.1.8",
    "@iconify/vue": "^4.1.1",
    "@kevinmarrec/nuxt-pwa": "^0.17.0",
    "@mdi/font": "^7.2.96",
    "@nuxtjs/google-fonts": "^3.0.0",
    "@pinia-plugin-persistedstate/nuxt": "^1.1.1",
    "nuxt": "3.4.2",
    "sass": "^1.62.0",
    "vuetify": "^3.1.15"
  },
  "dependencies": {
    "@pinia/nuxt": "^0.4.11",
    "pinia": "^2.1.3",
    "vite-plugin-vuetify": "^1.0.2"
  }

Answer 1

As I mentioned in the comments, the correct way to implement real-time functionality is to use sockets. However, if you need to do it in a polling manner, you can write a guard, similar to the following example:

actions: {
  start() {
    if (this.timer.isRunning) return;

    this.timer.isRunning = true;
    this.syncTimer();

    this.timer.timer = setInterval(() => {
      if (this.timer.time > 0) {
        this.timer.time--;
      } else {
        clearInterval(this.timer.timer);
        this.reset();
      }
    }, 1000);
  },
  // ...
}

Hope it’s useful