详解ES6中的 Set Map 数据结构学习总结

  let arr1 = [\'Hello\', \'World\', \'ES6\']
  let set1 = new Set() 
  arr1.forEach(type => {
    set1.add(type)
  }) 

  let arr2 = [1,2,3,4,1,5,2]
  let set2 = new Set(arr2) 
  for (let type of set2) {
   console.log(type)
  }
  // 1
  // 2
  // 3
  // 4
  // 5

  // 方法1 
  [...new Set([1,2,3,1,2])] // 1 2 3
  
  // 方法2
  Array.from(new Set([1,2,3,1,2])) // 1 2 3

  let arr3 = [7,8,9]
  let set3 = new Set(arr3)
  set3.add(10)
  set3.size() // 4
  set3.delete(8)
  set3.size() // 3
  set3.clear() // 0

  let arr4 = [\' \', \'vue\', \'node.js\', \'type \']
  let set4 = new Set(arr4) 
  
  // set.keys()
  for (let k of set4.keys()) {
   console.log(k)\\
   //  
   // vue 
   // node.js
   // type 
  } 

 // set.values()
 for (ket v of set4.values()) {
  console.log(v)
  // 和上面的set4.keys() 遍历的结果一样
 } 

 // set.entries()
 for (let e of set3.entries()) {
  console.log(e)
  // [\' \', \' \']
  // [\'vue\', \'vue\']
  // [\'node.js\', \'node.js\']
  // [\'type \', \'type \']
 }