JavaScript 覆盖对象字段级别

/**
 *  把source的字段，覆盖设置到target的字段，递归覆盖，不直接覆盖对象
 * @param target
 * @param source
 */
function extend(target, source) {
    for (let key in source) {
        let newValue = source[key];
        let oldValue = target[key];
        //如果 是数组，有值就追加，没值就覆盖
        if (Array.isArray(oldValue)) {
            target[key] = [...oldValue, ...newValue];
        } else if (typeof (oldValue) == "object") {
            //如果是object 递归设置
            target[key] = extend(oldValue, newValue);
        } else {
            //判断，如果不是object，就直接设置
            //普通字段
            target[key] = newValue;
        }

    }

    return target
}


var a = {
    obj: {
        name: '张三',
        age: 18,
        student: {
            name: '王五',
            classes: {
                name: '1年级1班',
                teacher: {
                    name: '王老师',
                    age: 20
                }
            }
        }
    },
    array: [{
        c: 13
    }, {
        b: 22
    }],
    aint: 10,
    astring: '123'
}

var b = {
    obj: {
        name: '李四',
        aaa: '555',
        student: {
            ss: '321',
            classes: {
                aget: 18,
                teacher: {
                    age: 30
                }
            }
        }
    }
}

// let temp = Object.assign(a, b);
let temp = extend(a, b);
console.log(JSON.stringify(temp, "", "\t"));