let palindrome = (str) => {
    let lastEl = str.length - 1
    let result = ''

    for (el in str) {
        result = str[el] === str[lastEl - el] ? 'yes' : 'no'
        if (result === 'no'){ return result}
    }
    return result
  }

[
  {
    "id": "852",
    "slug": "macbook-air-2020",
    "name_ru": "MacBook Air 2020",
    "parent": "102"
  },
  {
    "id": "850",
    "slug": "ipad-pro-2020",
    "name_ru": "iPad Pro 2020",
    "parent": "70"
  },
  {
    "id": "849",
    "slug": "iphone-se-2020",
    "name_ru": "iPhone SE 2020",
    "parent": "707"
  },
  {
    "id": "845",
    "slug": "macbook-air-2019",
    "name_ru": "MacBook Air 2019",
    "parent": "102"
  },
  {
    "id": "842",
    "slug": "macbook-pro-2019",
    "name_ru": "MacBook Pro 2019",
    "parent": "99"
  },
]

ildren: [842, 845, 849]

b.map((o) => { const children = b.filter(c => c.parent === o.id); return { children, id: o.id, name_ru: o.name_ru } })