多维数组转一维数组

  1. function flag(array) {
  2.     let length = array.length;
  3.     if (length === 0) return array;
  4.     let ret = [];
  6.     for (let item of array) {
  7.         if (item.constructor === Array) {
  8.             ret = ret.concat(flag(item));
  9.         } else {
  10.             ret.push(item);
  11.         }
  12.     }
  13.     return ret;
  14. }
  15. var mulitArray = [[1, [45, 23, 44], 1], 4, 25];
  16. flag(mulitArray);
  18. // [ 1, 45, 23, 44, 1,  4, 25 ]

两个数组的交集

  1. function intersection(array1 = [], array2 = []) {
  2.     return array1.filter(item => array2.includes(item));
  3. }
  4. var array1 = [1, 2, 3, 4, 5];
  5. var array2 = [4, 5, 6, 53];
  6. intersection(array1, array2);
  8. // [ 4, 5 ]

深拷贝

  1. function deepCopy(target) {
  2.   if (typeof target !== "object") return target;
  3.   let ret;
  5.   if (Array.isArray(target)) {
  6.     ret = target.map(item => deepCopy(item));
  7.   } else {
  8.     ret = {};
  9.     Object.keys(target).forEach(item => {
  10.       ret[item] = deepCopy(target[item]);
  11.     });
  12.   }
  13.   return ret;
  14. }
  16. var data = [1, 2, 3, { name: "xiaoming" }];
  17. // var data = { name: "小红", age: [23, 4] };
  18. // var data = [1, 2, 3, [4, 1, 5]];
  19. var result = deepCopy(data);