Question

How to copy part of array to another location in the same array without modifying its size in JavaScript

Answer 1

// arr.copyWithin(target[, start[, end]])

var arr = [1, 2, 3, 4, 5];
 
arr.copyWithin(0, 1, 2);
for (i = 0; i < arr.length; i++)
  document.write("arr[" + i + "] = " + arr[i] + "<br />"); 

/*
run:  

arr[0] = 2
arr[1] = 2
arr[2] = 3
arr[3] = 4
arr[4] = 5

*/

 

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Answer 2

// arr.copyWithin(target[, start[, end]])

var arr = [1, 2, 3, 4, 5];
 
arr.copyWithin(0, 1, 3);
for (i = 0; i < arr.length; i++)
  document.write("arr[" + i + "] = " + arr[i] + "<br />"); 

/*
run:  

arr[0] = 2
arr[1] = 3
arr[2] = 3
arr[3] = 4
arr[4] = 5

*/

 

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