深拷贝手写

function deepClone(obj = {}) {
    if (typeof obj !== 'object' || obj == null) {
        return obj;
    }
    
    let result
    if (obj instanceof Array) {
        result = []
    } else {
        result = {}
    }
    
    for (let key in obj) {
        if (obj.hasOwnProperty(key)) {
            result[key] = deepClone(obj[key])
        }
    }
    
    return result
}