cloneDeep#

import { cloneDeep } from 'funtool';

// 深度克隆对象
const original = { name: "Alice", details: { age: 25 } };
const copy = cloneDeep(original);
console.log(copy.details.age); // 25
console.log(copy !== original); // true

// 深度克隆包含嵌套对象的数组
const arr = [1, { nested: true }, [3]];
const copy = cloneDeep(arr);
console.log(copy[1].nested); // true

// 深度克隆Map
const map = new Map<string, number>([["a", 1], ["b", 2]]);
const copy = cloneDeep(map);
console.log(copy.get("b")); // 2

// 深度克隆Set
const set = new Set([1, 2, 3]);
const copy = cloneDeep(set);
console.log(copy.has(2)); // true

// 深度克隆Date
const date = new Date("2020-01-01");
const copy = cloneDeep(date);
console.log(copy.getFullYear()); // 2020

// 深度克隆RegExp
const regex = /abc/gi;
const copy = cloneDeep(regex);
console.log(copy.source); // "abc"
console.log(copy.flags); // "gi"

// 处理循环引用
const obj: any = {};
obj.self = obj;
const copy = cloneDeep(obj);
console.log(copy.self === copy); // true

type CloneDeep<T> =
  // 保留原始类型和函数不变
  T extends Primitive | ((...args: any[]) => any)
    ? T
    : // 如果是元组，保留精确的索引类型
    IsTuple<T> extends true
    ? { [K in keyof T]: CloneDeep<T[K]> }
    : // 如果是数组(非元组)，深度拷贝元素
    T extends ReadonlyArray<infer U>
    ? Array<CloneDeep<U>>
    : // 深度拷贝Map值
    T extends Map<infer K, infer V>
    ? Map<K, CloneDeep<V>>
    : // 深度拷贝Set值
    T extends Set<infer U>
    ? Set<CloneDeep<U>>
    : // 保留特定的内置对象类型
    T extends Date
    ? Date
    : T extends RegExp
    ? RegExp
    : // 深度拷贝普通对象，移除`readonly`并保留Symbol键
    T extends object
    ? {
        -readonly [K in keyof T]: CloneDeep<T[K]>;
      } & {
        [K in keyof T as K extends symbol ? K : never]: CloneDeep<T[K]>;
      }
    : T;
    
function cloneDeep<T>(obj: T, seen: WeakMap<object, any> = new WeakMap()): CloneDeep<T>