Oct 20, 2010 · To make an independent copy of an array rather than a copy of the refence to it, you can use the array slice method. Example: To make an independent copy of an array rather than a copy of the refence to it, you can use the array slice method. var oldArray = ["mip", "map", "mop"]; var newArray = oldArray.slice(); To copy or clone an object :

2) Using slice method, slice is for slicing part of the array, it will slice some part of your array without touching the original, in the slice, if don't specify the start and end of the array, it will slice the whole array and basically make a full copy of the array, so we can easily say:

May 5, 2017 · Creating a deep copy with structuredClone. The modern way to deep copy an array in JavaScript is to use structuredClone: array2 = structuredClone(array1); This function is relatively new (Chrome 98, Firefox 94) and is currently available to about 95% of users, so may not ready for production without a polyfill.

Dec 7, 2012 · var len = arr.length, copy = new Array(len); // boost in Safari for (var i=0; i<len; ++i) copy[i] = arr[i].slice(0); To extend to higher-dimensional arrays, either use recursion or nested for loops! The native slice method is more efficient than a custom for loop, yet it does not create deep copies, so we can use it only at the lowest level.

Sep 23, 2008 · See Corban's answer for benchmarks.. Reliable cloning using a library. Since cloning objects is not trivial (complex types, circular references, function etc.), most major libraries provide function to clone objects.

Aug 22, 2012 · I have two arrays: ArrayA and ArrayB. I need to copy ArrayA into ArrayB (as opposed to create a reference) and I've been using .splice(0) but I noticed that it seems to removes the elements from the initial array. In the console, when I run this code:

Oct 2, 2012 · Best way is << let B = JSON.parse(JSON.stringify(A)) >> As it is like a stream of data. The concept of reference is due to deep copy & shallow copy. In Deep copy reference will not be there, where as it will be there in shallow copy like << let B = A >>. Deep copy has some demerit like in custom object, nested object.

I want to form an array from an existing array so I can modify the new array without affecting the old. I realise arrays are mutable and this is why the new array affects the old. E.g. old = ["Apples", "Bananas"]; new = old; new.reverse(); Old has also been reversed.

Feb 13, 2015 · This function (Array.prototype.copy) uses recursion to recall it self when an object or array is called returning the values as needed. The process is decently speedy, and does exactly what you would want it to do, it does a deep copy of an array, by value... Tested in chrome, and IE11 and it works in these two browsers.

Update - Array.prototype.toSorted() proposal. The Array.prototype.toSorted(compareFn) -> Array is a new method that was proposed to be added to the Array.prototype and is currently in stage 3 (Soon to be available). This method will keep the target Array untouched and return a copy with the change performed instead.