Error in assigning elements in array in JS

Question

i am trying to store list data into an object received from axios response. the first set of data being headers i am storing in cols as array and the rest in rows. The data received is all defined and after parsing it perfectly logged in the console ie all defined. inside the loop when loading of rows elements starts, the first set of elements gets stored but for the next set ie for the value of i = 2 I am getting error saying cannot set property of undefined (setting 0).

For convenience I have changed the type of data received from the axios

        let response = {data:'"A","B"\n"C","D"\n"E","F"'} //await axios(URL)
        let raw = response.data.split(/\r?\n/);
        let data = {
            cols:[],
            rows:[]   // I have tried rows:[[]] or rows:[{v:[]}]
        }

        for (let i in raw) {
            raw[i] = raw[i].split(",");
            for(let j in raw[i]){
                raw[i][j] = raw[i][j].replace(/"/g, '')
                if (i==0)
                    data.cols[j]=raw[i][j]
                else{
                    data.rows[i-1][j]=raw[i][j] // for rows as object => data.rows[i-1].v[j]
                    //console.log(i+'->'+data.rows[i-1])
                }
            }        
        }
        return data // this is not matter of concern
    }

I have tried declaring the row array as 2D array but error persists. hoving the mouse over the object gives rows (property) : never[] and same with cols.

{cols:['A','B'], rows:[['C','D'],['E','F']]} something like that — Mohammed Tausif Raza Khan
– Mohammed Tausif Raza Khan, Commented Jun 10, 2022 at 8:39
if variable raw is storing data as an array then do not use for in loop rather than use forEach or map or normal for loop or while. — HiddenOne1254
– HiddenOne1254, Commented Jun 10, 2022 at 9:57

Yosvel Quintero · Accepted Answer · 2022-06-10 09:02:27Z

1

You can do:

const response = { data: '"A","B"\n"C","D"\n"E","F"' }
const [cols, ...rows] = response.data.split(/\r?\n/).map(r => r.match(/[A-Z]+/g))
const data = { cols, rows }

console.log(data)

edited Jun 10, 2022 at 9:02

answered Jun 10, 2022 at 8:55

Yosvel Quintero

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R4ncid · Accepted Answer · 2022-06-10 08:49:00Z

1

You can do something like this

let response = {data:'"A","B"\n"C","D"\n"E","F"'}

const [cols, ...rows] = response.data.split('\n').map(r => r.replace(/"/g, '').split(','))

const data = {
  cols,
  rows
}

console.log(data)

answered Jun 10, 2022 at 8:49

R4ncid

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