SOURCE

const array = [
  {id: 1, phone: "13712345678"},
  {id: 2, phone: "18612345670"},
  {id: 3, phone: "13712345678"},
  {id: 4, phone: "13712345678"},
  {id: 5, phone: "18612345670"},
  {id: 6, phone: "13777777777"},
];

const checkSame = array => {
  let result = {}
  array.map((item)=>{
    if(result[item.phone]){
      result[item.phone].push(item);
    } else {
      result[item.phone] = [item]
    }
  })
  for(let i=0; i<result.length; i++){
    if(result[i].length === 1){
      delete result result[i]
    } else {
      result[i] = {
        number: `重复数量：${item.length}`,
        list: item
      }
    }
  }
  return result;
}

(() => {
  const result = JSON.stringify(checkSame(array));
  document.write(`发现重复的数据：<br />${result}`)
})();