Extending data of an existing object from an array

Question

I receive arrays from an API in a JSON format. I want to merge them into the nested array called which consists of objects graphData . How do I extend the data object by one entry?

mounted() {

   var i = 0;
   const axios = require('axios');
    //Usage
    axios.get("https://3.11.40.69:9001/app/usageUnitForCustomer/1521/2019-12-30/2020-12-30")
      .then(response => {
        const time = response.data.event_time; //["2019-12-30T14:06:21.000Z", "2019-12-30T14:06:21.000Z"]
        const unit = response.data.unit; //[44.67, 75.89]
        for (i = 0; i < 1; i++) {
          if (time[i] !== time[i + 1]) {
            this.graphData[1].data.time[i] = unit[i];
          }
        } 
      })
    //Revenue
    axios.get("https://3.11.40.69:9001/app/revenueUnitForMachine/345/2019-12-30/2020-12-30")
      .then(response => {
        const time = response.data.event_time; //["2019-12-30T14:06:21.000Z", "2019-12-30T14:06:21.000Z"]
        const unit = response.data.revenue; //[44, 75]
        for (i = 0; i < 10; i++) {
          if (time[i] !== time[i + 1]) {
            this.graphData[0].data.time[i] = unit[i];
          }
        } 

      })
  },
  data() {
      return {
        graphData: [
          {name: 'Revenue', data: {}},
          {name: 'Usage', data: {}}
        ]
      }
    }

After executing the above code both data objects are still empty. The outcome looks like this and following error message:

0:
name: "Revenue"
data: Object []

1:
name: "Usage"
data: Object []

Uncaught (in promise) TypeError: Cannot set property '0' of undefined

Expected outcome:

graphData: [
          {name: 'Revenue', data: {'2019-12-30T14:06:21.000Z': 448, '2019-12-30T14:06:22.000Z': 44}},
          {name: 'Usage', data: {'2019-12-30T14:06:21.000Z': 448, '2019-12-30T14:06:22.000Z': 44}}
        ]

Has anyone an idea?

Answer 1

You cannot reach outside variables from within a .then() block. You should be able to make the whole outside block into an async and use await for your axios calls.

Try something like this:

async mounted() {

   var i = 0;
   const axios = require('axios');
    //Usage

   const response = await axios.get("https://3.11.40.69:9001/app/usageUnitForCustomer/1521/2019-12-30/2020-12-30");

        const time = response.data.event_time;
        const unit = response.data.unit;
        for (i = 0; i < 1; i++) {
          if (time[i] !== time[i + 1]) {
            this.graphData[1].data.time[i] = unit[i];
          }
        } 


...

... continue to use await for the rest of your axios calls.

Answer 2

One issue I see is that you access time[i] in this.graphData[1].data.time[i] = unit[i]; but it is not defined inside your objects.

Maybe initializing it as an array helps?

data() {
    return {
        graphData: [
          {name: 'Revenue', data: { time: [] }},
          {name: 'Usage', data: { time: [] }}
        ]
    }
}

Edit: Ok, after you edited the expected outcome I see another issue.

Can you try setting the value like this?

this.graphData[1].data[time[i]] = unit[i];

Note the extra [] around time[i] .