深拷贝

平常我们都是用JSON来做复杂数据类型的拷贝,但是如果遇到有undefined,NaN,函数这些数据,使用JSON就会被转译,达不到期望的拷贝效果,所以如果有以上情况就需要是用递归来拷贝啦

 <script>
        
        function deepCopy(current, additive) {
            // 深拷贝函数
            // 参数一:需要添加拷贝的数据
            // 参数二:被拷贝的数据
            if ((typeof additive) != 'object') {
                current = additive;
            } else {
                if ((typeof current) == 'undefined' || current.constructor != additive.constructor) {
                    current = new (additive.constructor);
                }
                function recur(c, a) {
                    for (let key in a) {
                        if ((typeof a[key]) == 'object') {
                            if ((typeof c[key]) == 'undefined' || c[key].constructor != a[key].constructor) {
                                c[key] = new (a[key].constructor);
                            }
                            recur(c[key], a[key]);
                        } else {
                            c[key] = a[key];
                        }
                    }
                }
                recur(current, additive);
            }
            return current;
        }


        let data = {
            a: [1, 2, 3],
            b: '55'
        }

        let state = {
            a: '1',
            b: {
                c: '2',
                d: [3, {
                    e: '4'
                }]
            },
            s: function (v) {
                return v + 2;
            }

        }

        // 测试一下
        // 将state拷贝给data
        data = deepCopy(data, state);
        console.log(data);
        console.log(data.s(2));

    </script>