Hand lift deep copy

function deepClone(obj, hash = new WeakMap()) { if (obj === null) return obj; If (obj instanceof Date) return new Date(obj); if (obj instanceof Date) return new Date(obj); if (obj instanceof RegExp) return new RegExp(obj); If (typeof obj! == "object") return obj; If (hash. Get (obj)) return hash. Get (obj); let cloneObj = new obj.constructor(); Set (obj, cloneObj); // Constructor points to the current class's own hash.set(obj, cloneObj); For (let key in obj) {if (obj.hasOwnProperty(key)) {cloneObj[key] = deepClone(obj[key], hash); } } return cloneObj; } let obj = { name: 1, address: { x: 100 } }; obj.o = obj; // let d = deepClone(obj); obj.address.x = 200; console.log(d);Copy the code