浅拷贝

Object.assign(target, source1, source2)

深拷贝

1 deepcopy

      function deepCopy(obj, newObj) {
        newObj = newObj || {};
        for (var key in obj) {
          if (typeof obj[key] === "object") {
            newObj[key] = Array.isArray(obj[key]) ? [] : {};
            deepCopy(obj[key], c[key]);
          } else {
            newObj[key] = obj[key];
          }
        }
        return newObj;
      }

2 jQuery的$.extend()
3 JSON.parse(JSON.stringify(obj));
4 lodash_.cloneDeep()
5 clone = structuredClone(original)

• 对数组的深拷贝

let box = list.slice();
let box = [].concat(list); 
let box = [...list];
let box = Array.from(list);