export default {
    deepCopy(target) {
        const map = new WeakMap()
        
        function isObject(target) {
            return (typeof target === 'object' && target ) || typeof target === 'function'
        }
    
        function clone(data) {
            if (!isObject(data)) {
                return data
            }
            if ([Date, RegExp].includes(data.constructor)) {
                return new data.constructor(data)
            }
            if (typeof data === 'function') {
                return new Function('return ' + data.toString())()
            }
            const exist = map.get(data)
            if (exist) {
                return exist
            }
            if (data instanceof Map) {
                const result = new Map()
                map.set(data, result)
                data.forEach((val, key) => {
                    if (isObject(val)) {
                        result.set(key, clone(val))
                    } else {
                        result.set(key, val)
                    }
                })
                return result
            }
            if (data instanceof Set) {
                const result = new Set()
                map.set(data, result)
                data.forEach(val => {
                    if (isObject(val)) {
                        result.add(clone(val))
                    } else {
                        result.add(val)
                    }
                })
                return result
            }
            const keys = Reflect.ownKeys(data)
            const allDesc = Object.getOwnPropertyDescriptors(data)
            const result = Object.create(Object.getPrototypeOf(data), allDesc)
            map.set(data, result)
            keys.forEach(key => {
                const val = data[key]
                if (isObject(val)) {
                    result[key] = clone(val)
                } else {
                    result[key] = val
                }
            })
            return result
        }
        // clone(target)
        return JSON.parse(JSON.stringify(target));
    }
    
}