SOURCE

const log = console.warn
console.clear()

const dataToTree = data => {
    const parent = data.filter(
        (value) => value.parent === "undefined" || value.parent == null || value.parent == ""
    )
    const children = data.filter(
        (value) => value.parent !== "undefined" && value.parent != null && value.parent !== ""
    )
    const translator = (parent, children) => {
        parent.forEach((parent) => {
            children.forEach((current, index) => {
                if (current.parent === parent.name) {
                    translator([current], children)
                    Array.isArray(parent.children) ? parent.children.push(current) : (parent.children = [current])
                    current.parent = parent
                }
            })
        })
    }
    translator(parent, children)
    return parent
}
const processCsv = csv => {
    let processedArr = csv.split('\n').filter(item => item !== "")
    let keys = processedArr.shift().split(',')
    let obj = processedArr.map(item => {
        return item.split(',').reduce((tol, cur, i) => {
            if (keys[i] === 'parent' && cur === '') {
                cur = null
            }
            return { ...tol, [`${keys[i]}`]: cur }
        }, { children: null })
    })
    return dataToTree(obj)
}

const csv = `
name,age,parent
Bob,30,David
David,60,
Anna,10,Bob
Anna2,10,Bob
`

let result = processCsv(csv)
log(result)