[FIXED] How to auto refresh a computed property at axios in vuejs

Issue

I'm calling restapi data with axios in vuejs , i want this data to be auto refreshed everysecond to see any change in numbers. I can see data, its working but refresh is not working

I've put setinterval function in methods area but it doesnt refresh any data.

import axios from 'axios';    
export default {    
  data () {    
    return {    
      btctrk: null,    
      bnnc: null,    
    }    
  },    
  computed: {    
          result1: function(){    
              return  this.btctrk[0].ask / this.btctrk[4].bid;    
          },    
          result2: function(){    
              return  this.btctrk[0].bid / this.btctrk[4].ask;    
          },    
          result3: function(){    
              return  (1-(this.bnnc[11].bidPrice / this.result1))*100;    
          },    
          result4: function(){    
              return (1-(this.result2 / this.bnnc[11].askPrice))*100;    
          },    
      },    
  mounted () {    
    axios    
      .get('https://www.api1.com/api/ticker')    
      .then(response => (this.btctrk = response.data))    
      .catch(error => console.log(error))    
    axios    
      .get('https://api.api2.com/api/v3/ticker/bookTicker')    
      .then(response => (this.bnnc = response.data))    
      .catch(error => console.log(error))    
  },    
  methods: {    
              startInterval: function () {    
                   setInterval(() => {    
                      this.result1;    
                      this.result2;    
                      this.result3;    
                      this.result4;    
                   }, 1000);    
          }    
  }    
}

Solution

Computed properties are only re-evaluated if some of its dependencies have changed, meaning that they have some sort of "cache" if we can put it like that. See: Computed caching vs Methods

Another thing is that you are running your Axios get call when mounted(), meaning that your call is only running once the component is mounted and not refreshing at all. See: Lifecycle Diagram

My solution to your problem will be something like this:

  export default {
    data () {    
        return {    
        btctrk: null,    
        bnnc: null,    
        }    
    },    
    computed: {
        result1: function(){    
            return  this.btctrk[0].ask / this.btctrk[4].bid;    
        },    
        result2: function(){    
            return  this.btctrk[0].bid / this.btctrk[4].ask;    
        },    
        result3: function(){    
            return  (1-(this.bnnc[11].bidPrice / this.result1))*100;    
        },    
        result4: function(){    
            return (1-(this.result2 / this.bnnc[11].askPrice))*100;    
        },    
    },
    methods: {
        btcTrkAPICall: function () {
            axios    
                .get('https://www.api1.com/api/ticker')    
                .then(response => (this.btctrk = response.data))    
                .catch(error => console.log(error))    
        },
        bnncAPICall: function () {
            axios    
                .get('https://api.api2.com/api/v3/ticker/bookTicker')    
                .then(response => (this.bnnc = response.data))    
                .catch(error => console.log(error))    
        },
        intervalFetchData: function () {
            setInterval(() => {    
                this.btcTrkAPICall();
                this.bnncAPICall();
                }, 1000);    
        }
    },
    mounted () {
        // Run the functions once when mounted 
        this.btcTrkAPICall();
        this.bnncAPICall();
        // Run the intervalFetchData function once to set the interval time for later refresh
        this.intervalFetchData();
    }
}

I think this is a plausible solution, feel free to test it out.

Answered By - Luis Maldonado

Answer Checked By - Gilberto Lyons (PHPFixing Admin)