SOURCE

{
  let obj = {
    a: 1
  };
  let t_arr = [[1, 2], [3, 4]];
  let list = new Set();
  list.add(5);
  list.add(obj);
  list.add(t_arr);
  // console.log(list);
} {
  let arr = [1, 3, 2, 4, 4, 3, 2, 67, 8, 9];
  let list = new Set(arr);
  // console.log(list.size);
} {
  let arr = ['ab', 'cdf', 'abc'];
  // console.log(arr.indexOf('ab'));
  let list = new Set(arr);
  // console.log(list.has('ab'));
  // console.log(list.delete('ab'),list);
  // console.log(arr);
} {
  let arr = ['ab', 'cdf', 'abc'];
  let list = new Set(arr);
  for (let value of list.values()) {
    // console.log(value);
  }
} {
  let arr = ['ab', 'cdf', 'abc'];
  arr.splice(arr.indexOf('ab'), 1);
  // console.log(arr);
} {
  let map = new Map([['a', 123], ['b', 456]]);
  // console.log(map);
} {
  let array = [];
  array.push({
    t: 1
  });
  array.push({
    t: 2
  });
  array.push({
    t: 1
  });
  let index = array.filter(item => {
    return item.t == 1;
  });
  // console.log(index);
} 
{
  let item = {
    t: 1
  };
  let map = new Map();
  let set = new Set();
  let obj = {};
  //增
  map.set('t', 1);
  set.add(item);
  obj['t'] = 1;
  map.set('t',2);
item.t = 2;
obj['t'] = 2;
  delete obj['t']
}
{
   let item = {
    t: 1,
     m:3
  };
  delete item['t']
  console.log(item);
}
{
  let arr_obj=[
    {a:1,b:2},
    {a:2,b:3}
  ];
  arr_obj.forEach(item=>{
      Object.assign(item,{c:'c'})
  });
  console.log(arr_obj);
}
{
  let arr_obj=[
    {a:1,b:2},
    {a:2,b:3}
  ];
  arr_obj.forEach(item=>{
    delete item['a']
  });
  console.log(arr_obj);
}