function type(data) { return Object.prototype.toString.call(data).slice(8, -1).toLowerCase(); } function clone(source) { const t = type(source) if (t !== 'object' && t !== 'array') { return source } let target if (t === 'object') { target = {} for (let i in source) { if (source.hasOwnProperty(i)) { target[i] = clone(source[i]) // ! } } } else { target = [] for (let i = 0; i < source.length; i++) { target[i] = clone(source[i]) // ! } } return target } let a = { c: 1 } let b = clone(a) // 深拷贝 a.c = 2 console.log(a.c) // 2 console.log(b.c) // 1