https://developer.mozilla.org/en-US/docs/Web/API/structuredClone
var clone = (function(){
// classify object
var classof = function(o){
if (o === null) { return "null"; }
if (o === undefined) { return "undefined"; }
// I suppose Object.prototype.toString use obj.constructor.name
// to generate string
var className = Object.prototype.toString.call(o).slice(8,-1);
return className;
};
var references = null;
var handlers = {
// Handle regexp and date even in shallow.
'RegExp': function(reg) {
var flags = '';
flags += reg.global ? 'g' : '';
flags += reg.multiline ? 'm' : '';
flags += reg.ignoreCase ? 'i' : '';
return new RegExp(reg.source, flags);
},
'Date': function(date) {
return new Date(+date);
},
'Array': function(arr, shallow) {
var newArr = [], i;
for (i=0; i<arr.length; i++) {
if (shallow) {
newArr[i] = arr[i];
} else {
// handle circular reference
if (references.indexOf(arr[i]) !== -1) {
continue;
}
var handler = handlers[classof(arr[i])];
if (handler) {
references.push(arr[i]);
newArr[i] = handler(arr[i], false);
} else {
newArr[i] = arr[i];
}
}
}
return newArr;
},
'Object': function(obj, shallow) {
var newObj = {}, prop, handler;
for (prop in obj) {
if (obj.hasOwnProperty(prop)) {
// escape prototype properties
if (shallow) {
newObj[prop] = obj[prop];
} else {
// handle circular reference
if (references.indexOf(obj[prop]) !== -1) {
continue;
}
// recursive
handler = handlers[classof(obj[prop])];
if (handler) {
references.push(obj[prop]);
newObj[prop] = handler(obj[prop], false);
} else {
newObj[prop] = obj[prop];
}
}
}
}
return newObj;
}
};
return function(obj, shallow) {
// reset references
references = [];
// default to shallow clone
shallow = shallow === undefined ? true : false;
var handler = handlers[classof(obj)];
return handler ? handler(obj, shallow) : obj;
};
}());
(function(){
// Following is some tests
var date = new Date();
var reg = /hello word/gi;
var obj = {
prop: 'this ia a string',
arr: [1,2,3],
o: {
wow: 'aha'
}
};
var refer1 = {
arr: [1,2,3]
};
var refer2 = {
refer: refer1
};
refer1.refer = refer2;
var cloneDate = clone(date, false);
var cloneReg = clone(reg, false);
var cloneObj = clone(obj, false);
alert( (date !== cloneDate) && (date.valueOf() === cloneDate.valueOf()) );
alert( (cloneReg !== reg) && (reg.toString() === cloneReg.toString()) );
alert( (obj !== cloneObj) && (obj.arr !== cloneObj.arr) && (obj.o !== cloneObj.o) && (JSON.stringify(obj) === JSON.stringify(cloneObj)) );
clone(refer2, false);
alert("I'm not dead yet!");
// Output:
// true
// true
// true
// I'm not dead yet!
}());
