Pavel's questions

let massive = [
  ["Mallory", "Everest", "Mont Blanc", "Pillar Rock"],
  ["Mawson", "South Pole", "New Hebrides"],
  ["Hillary", "Everest", "South Pole"]
];


function func(massive) {


  let toponymes = [];
  let explorers = [];
  let result = [];

  for (let i = 0; i < massive.length; i++) {
    explorers = [...explorers, massive[i][0]]
    // выписываем всех исследователей
    massive[i].map((topo) => {
      if (massive[i][0] != topo) {
        toponymes = [...toponymes, topo]
        // выписываем все топонимы
      }
    })
  }
  toponymes = [...new Set(toponymes)]; //исбавляемся от дубликатов



  toponymes.map((t, id) => {
    for (let i = 0; i < massive.length; i++) {
      massive[i].map((m) => {

        if (m == t) {

          if (result[id] === undefined) {
            result[id] = [toponymes[id], explorers[i]]
          } else {
            result[id] = [...result[id], toponymes[id], explorers[i]]
          }
          result[id] = [...new Set(result[id])];
        }
      })
    }
  })
  console.log(result)
  return (result)

}
func(massive)