Comment cloner correctement un objet JavaScript

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function clone(obj) {     if (null == obj || "object" != typeof obj) return obj;     var copy = obj.constructor();     for (var attr in obj) {         if (obj.hasOwnProperty(attr)) copy[attr] = obj[attr];     }     return copy; }  var d1 = new Date();  /* Executes function after 5 seconds. */ setTimeout(function(){     var d2 = clone(d1);     alert("d1 = " + d1.toString() + "\nd2 = " + d2.toString()); }, 5000); 

function clone(obj) {     var copy;      // Handle the 3 simple types, and null or undefined     if (null == obj || "object" != typeof obj) return obj;      // Handle Date     if (obj instanceof Date) {         copy = new Date();         copy.setTime(obj.getTime());         return copy;     }      // Handle Array     if (obj instanceof Array) {         copy = [];         for (var i = 0, len = obj.length; i < len; i++) {             copy[i] = clone(obj[i]);         }         return copy;     }      // Handle Object     if (obj instanceof Object) {         copy = {};         for (var attr in obj) {             if (obj.hasOwnProperty(attr)) copy[attr] = clone(obj[attr]);         }         return copy;     }      throw new Error("Unable to copy obj! Its type isn't supported."); } 

// This would be cloneable: var tree = {     "left"  : { "left" : null, "right" : null, "data" : 3 },     "right" : null,     "data"  : 8 };  // This would kind-of work, but you would get 2 copies of the  // inner node instead of 2 references to the same copy var directedAcylicGraph = {     "left"  : { "left" : null, "right" : null, "data" : 3 },     "data"  : 8 }; directedAcyclicGraph["right"] = directedAcyclicGraph["left"];  // Cloning this would cause a stack overflow due to infinite recursion: var cyclicGraph = {     "left"  : { "left" : null, "right" : null, "data" : 3 },     "data"  : 8 }; cyclicGraph["right"] = cyclicGraph; 

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const a = {    string: 'string',    number: 123,    bool: false,    nul: null,    date: new Date(),  // stringified    undef: undefined,  // lost    inf: Infinity,  // forced to 'null'  }  console.log(a);  console.log(typeof a.date);  // Date object  const clone = JSON.parse(JSON.stringify(a));  console.log(clone);  console.log(typeof clone.date);  // result of .toISOString()

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var copiedObject = jQuery.extend({}, originalObject) 

var copiedObject = jQuery.extend(true, {}, originalObject) 

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var x = {myProp: "value"}; var y = Object.assign({}, x);