手写深拷贝
function isObject(obj) {
return Object.prototype.toString.call(obj).slice(8, -1) === "Object"
}
function deepClone(obj, hash = new WeakMap()) {
if (obj === null) return obj;
if (obj instanceof Date) return new Date(obj)
if (obj instanceof RegExp) return new RegExp(obj)
if (!isObject(obj)) return obj
let newObj = Array.isArray(obj) ? [] : {}
if (hash.has(obj)) return hash.has(obj)
let symbolKeys = Object.getOwnPropertySymbols(obj)
if (symbolKeys && symbolKeys.length > 0) {
symbolKeys.forEach(el => {
if (isObject(obj[el])) {
newObj[el] = deepClone(obj[el], hash)
} else {
newObj[el] = obj[el]
}
})
}
for (let key in obj) {
if (obj.hasOwnProperty(key)) {
if (isObject(obj[key])) {
newObj[key] = deepClone(obj[key])
} else {
newObj[key] = obj[key]
}
}
}
return newObj;
}
let obj = {
name: "hl",
book: {
title: "You Don't Know JS",
price: "45"
},
a1: undefined,
a2: null,
a8: Symbol(1),
a3: 123
}
const sys1 = Symbol(1)
obj[sys1] = 'test'
console.log(deepClone(obj))
